About Kerv

What is Kerv?

Kerv is the world’s first Mastercard® contactless payment ring … and the first in an innovative range of next-generation wearable payment devices.

Kerv can be used to make a payment anywhere in the world that accepts standard contactless credit, debit and prepaid card payments.

Kerv uses similar technology to that which is in the contactless payment cards already in your wallet or purse, but we’ve obviously had to make an innovative leap or two to make that technology work as an attractive and comfortable wearable device.

Kerv also facilitates one-touch access to public transport networks.

How do I activate my Kerv ring?

You’ll need to activate your Kerv ring before you can use it to make a payment. Until your ring is activated, it is not associated with your Kerv Account and is completely inert.
Warning once you active your ring this cannot be reversed.

To activate your ring you must first register for a Kerv Virtual Prepaid Mastercard which can be completed in a matter of minutes by registering at kerv.com.

You may then link your Kerv ring to your Kerv Virtual Prepaid Mastercard by logging in to kerv.com and selecting Link Device from the Welcome Screen.

You will be asked to provide a Visual ID - this is the 9 digit code found in your rings box.

Once your Visual ID is entered your ring is now ready and you may add funds to your account

Are there any fees for using Kerv?

There are no fees for purchases with your Kerv ring.

You can load your Kerv Virtual Mastercard with funds via bank transfer or a debit card without incurring fees.

Please see the detailed view of our Fees and Limits for using the Kerv prepaid Mastercard programme.

How is Kerv associated with Mastercard?

The Kerv prepaid Mastercard programme is issued by PSI-Pay Ltd under license from Mastercard.

Mastercard has formally issued a contactless vendor product letter of approval for the Kerv contactless payment ring, as an M/Chip Advance Payment and Data Storage device.

How secure is my Kerv ring?

As Kerv uses the same technology as a contactless debit card transactions your ring is just as secure as your traditional method of payment. Furthermore, to make a payment with Kerv it must be within very close proximity to a contactless reader, and you hand must be in the Transmission Ready Position to avoid any unintended transfer of data or funds.

Transactions with Kerv over the Mastercard network are just as secure as using Chip & PIN. Your transactional data is always encrypted and because Kerv never leaves your finger, the risk of cloning or theft is significantly reduced.

Your Kerv Virtual Prepaid Mastercard is secure as you are protected by the stringent rules of the FCA, Kerv also provides you with all the tools you need to add further layers of security to your transactions, such as:

  • The ability to switch your ring on and off, anytime, anywhere
  • Constant background transactional risk assessments
  • Balance notifications

Why don’t I have to charge my Kerv ring?

The Kerv ring contains no battery and therefore never needs charging. The Kerv ring draws its power from the card reader during a contactless payment via electromagnetic induction.

Why don’t I have to pair my Kerv ring with my phone?

The Kerv ring contains all the technology required to directly connect with the Mastercard payment network, so it doesn’t need to be paired with a smartphone to make a payment. It just works all by itself.

Is my Kerv ring waterproof?

Yes! The inner bank of the Kerv ring is made from a hard inert resin which seals the electronics and renders it completely waterproof.

How tough is my Kerv ring?

The Kerv ring outer shell is made from zirconia ceramic (ZrO2), which is extremely tough, hard and scratch resistant.

It is significantly harder and more scratch resistant than traditional metal jewellery - even that made of titanium. However, it can still be damaged if dropped on hard surfaces, or a significant force is applied to it.



Gold and silver

2.5 - 3


4 - 4.5



Zirconia ceramic




Diagram of a kerv ring

This table should provide some context by showing where other common jewellery substances sit alongside zirconia ceramic on the Mohs scale of hardness:

Note: The Kerv ring can be scratched with diamond-coated nail files / emery boards, so they must be kept separate at all times. We recommend that you do not wear a Kerv ring during nail care.

Will my Kerv ring irritate my skin?

Kerv’s inner band is made from an inert resin that has been specifically created with health and safety in mind, so it’s very unlikely that your Kerv ring will irritate your skin during normal usage.

If you do experience any discomfort or irritation, please let us know immediately by emailing support@kerv.com

Will my Kerv ring expire?

Yes, your Kerv ring will expire – much like a credit or debit card – 4 years after the date of issue.

We will alert you 30 days before your Kerv ring expires to give you plenty of opportunity to order a replacement.

How should I dispose of my Kerv ring?

If you no longer want your Kerv ring, or if it has expired, we ask that you return it to us (free of charge), rather than disposing of it as part of your household waste. We don’t want our products to contribute towards landfill, and the combination of materials means that it will be hard for you to recycle Kerv yourself – so we’ll do it!

Contact support@kerv.com when you’re ready to dispose of your Kerv ring and we’ll take it from there.

What’s the Kerv Prepaid Mastercard?

The Kerv Prepaid Mastercard can be used to make transactions online, on the high street or over the phone, and has both Chip & PIN and contactless capabilities. The card draws funds from the same account as your ring.

What’s the Kerv Virtual Prepaid Mastercard?

Your Kerv Virtual Prepaid Mastercard funds the Kerv ring and the Kerv Prepaid Mastercard, with each device drawing from the same pool of funds. You can connect multiple Kerv devices (Card, Ring, Watch etc.) to the same Kerv Virtual Prepaid Mastercard.

The Kerv Virtual Prepaid Mastercard is for online use (such as e-commerce and in-app purchases) and telephone payments only – seeing as it doesn’t physically exist.

The Kerv Virtual Mastercard is a 16-digit long card number, an expiry date and a 3-digit security code, which is all you need to make a transaction online or over the phone. Find the details in Devices

Devices icon

As with any payment card, you should keep the details of your Kerv virtual card secure.

Funds, transactions and all Kerv Virtual Mastercard activity will always be displayed in your native currency by default.

Is Kerv authorised by the FCA in the UK?

Yes, via our e-money issuer, PSI-Pay Ltd. PSI-Pay Ltd is authorised by the Financial Conduct Authority of the United Kingdom under the Electronic Money Regulations 2011 (register reference 900011) for the issuing of electronic money.

Who makes the Kerv ring?

The Kerv Prepaid Mastercard programme is operated by Kerv Wearables Ltd, Registered office: Regent House, 316 Beulah Hill, London, SE19 3HF. Company number 10093360; VAT registration number 258044208.

The Kerv prepaid Mastercard programme is issued by PSI-Pay Ltd pursuant to a license by Mastercard International Incorporated. PSI-Pay Ltd is authorised by the Financial Conduct Authority of the United Kingdom under the Electronic Money Regulations 2011 (register reference 900011) for the issuing of electronic money.

How do I make a complaint?

Please email us at complaints@kerv.com We aim to rapidly resolve your complaint to your satisfaction.

If you feel that we have not resolved your complaint to your satisfaction, you can ask for a review from the Financial Ombudsman Service (FOS), an independent and government-backed service designed to help complainants who find themselves in a dispute with a financial organisation. After reviewing your complaint, the FOS will make an adjudication on our response.

You can write to the FOS at:
Financial Ombudsman Service
Exchange Tower
E14 9SR

Or email them: complaint.info@financial-ombudsman.org.uk
Or call them: 0800 023 4567

Our Complaints Handling Procedure can be downloaded here.

How do I contact Kerv?

You can contact us by:

Selecting Help at the bottom of the screen


 Emailing support@kerv.com

Write to us at:

Kerv Wearables
78 York Street
W1H 1DP. 

If your Kerv ring is lost or stolen, then call us immediately on 0844 502 0450.

Paying with Kerv

How do I make a payment with my Kerv ring?

To make a payment with your Kerv ring, just make a “knocking” gesture over the contactless card reader.

You will hear a beep and see a green light to signify a successful transaction. You don’t need to enter a PIN.

Where can I pay with my Kerv ring?

The Kerv ring can be used to make a payment anywhere in the world that accepts Mastercard contactless payments. This includes stores, restaurants, bars, cafes, cinemas, taxis and some public transport networks – just look out for the contactless payments symbol below.

Contactless payments symbol

Does my Kerv Account have an Auto top-up facility?

Yes, it does! Auto top-up means you never have to worry about your Kerv Account running low on funds, and your Kerv Ring not being accepted in-store. If your funds fall below a preset threshold, Auto top-up will automatically add funds of a specified amount to your Kerv Account.

Please note that Auto top-up takes place at 06:00 GMT each day, not at the precise time your funds fall below your preset threshold.

See how to use Auto top-up.

Can I make accidental payments with my Kerv ring?

No. The Kerv ring can only make a payment if it’s within 4cm of a contactless payment terminal, when your hand in is the Transmission Ready Position.

Also, transactions must be initiated by the retailer, which means that the contactless card reader is inactive until payment is specifically requested.

Is there a transaction limit with my Kerv ring?

The transaction limit for contactless payments in the UK is currently £30.

This limit does not apply to online or in-app purchases made with your Kerv Virtual Prepaid Mastercard.

Can I use my Kerv Ring abroad?

Yes: anywhere in the world that accepts Mastercard® contactless payments - currently over 6 million locations worldwide.

We use Mastercard’s foreign exchange rate, and any associated fees can be found in our Limits and Fees table.

As we use Mastercard’s foreign exchange rates, you may notice a slight difference in amount between the point when you make the transaction and when the charge is finalised with Mastercard, which could be up to two days later; this may show on your statement as an End of Day Balance Adjustment.

Can I use my Kerv ring to make online purchases?

When you register your Kerv ring, you are issued with a Kerv Virtual Prepaid Mastercard that allows you to make payments online, in-app or over the phone.

You can locate the card details by logging in and visiting the devices page and clicking your virtual card to reveal the 16-digit card number, expiry date and security code.

Note: Please keep the details of your virtual card private and secure. Do not share them with anyone.

Will I still get my usual loyalty points/rewards when I pay with my Kerv ring?

If you load your Kerv Account with a card with which you collect loyalty points or receive cashback, you may still receive these as a load will be categorised as a payment to Kerv Wearables.

This is dependant on your particular card issuer and we recommend checking with them.


What is the End of Day Balance Adjustment?

The End of Day Balance Adjustment is an amount either deducted from or added to the balance of your virtual Mastercard (which stores the funds accessed by your Kerv payment devices) to cover scenarios such as offline transactions – for example, a journey made on the TfL network –  which are not always deducted from your balance in real time, and are therefore reconciled at the end of the day; or when a foreign exchange transaction is authorised, it is deducted from your virtual Mastercard using the exchange rate at that moment, which may be different at the time of settlement, so is therefore reconciled via an End of Day Balance Adjustment.

Which type of Kerv Account do I have?

There are currently two types of Kerv Account, Lite and Standard, which have different limits and fees.

To see which account you have, first log in and go to “Account”.

At the top of the screen, click the arrow button next to your available balance to reveal more information about your account.

Extra functionality

How do I use Kerv on public transport?

At the moment, we can only offer information about using Kerv on the Transport for London network, where it can be used as a replacement for a ticket or Oyster Card.

You use Kerv on the TfL network in the same way in which you make a contactless payment, by “knocking” on the yellow Oyster Card reader pad. Ensure you hold the ring over the centre of the yellow pad, and wait until the reader beeps.

If you use Kerv on London’s public transport network, you’ll benefit not just from a daily cap, but also from a Monday to Sunday weekly cap, which means that it will never cost you more than a daily or weekly travelcard.  

However, it’s important to note that the cap runs Monday to Sunday, so if you were going to make many journeys in London over a seven day period that started on a day other than Monday, a weekly Oyster travelcard could be slightly cheaper. But less convenient!

Ordering Kerv

Are there any application or ordering restrictions?

Customers must meet age, residency and identification checks when applying for the Kerv virtual prepaid Mastercard account to which Kerv Ring is linked.

Customers must be 18 or over to register for the Kerv virtual prepaid Mastercard.

You don’t have to be over 18 to buy a Kerv Ring, but will need a valid debit or credit card, or PayPal account to make payment.

In which countries is Kerv available?

The Kerv ring is currently available in the UK, but over the coming months we will be making it available across Europe and then to other countries around the world

Do I have to be over 18 to buy a Kerv ring?

You don’t have to be over 18 to buy a Kerv ring, but will need a valid debit or credit card, or PayPal account to make payment.

You will need to be 18 or over to register for the Kerv virtual prepaid Mastercard to which the ring is linked.

How do I determine my ring size?

We always recommend getting your finger measured professionally by a jeweller. However, if that’s not an option for you, please see our guide to ring sizing.

We also offer ring sizers in the Kerv Store for taking your own measurement - but this will never be as accurate as a professional jeweller’s!

Which Kerv ring colours are available?

Kerv’s ceramic outer shell comes in black or white, and you can choose from 7 inner band colours: Ocean blue, Sun orange, Fire red, Leaf green, Candy pink, Jet black and Moon white.

You can see all the Kerv colour options in the Kerv Store.

Can I have more than one Kerv ring?

Yes, you can attach up to 3 rings to your Kerv Virtual Prepaid Mastercard, and they will all be sharing the funds, ideal if you want your ring to match your outfit!

You can turn off a ring that you are not using via the Devices page


Can I buy a Kerv ring as a gift?

Yes, you can. The Kerv ring isn’t linked to a specific Kerv Account until it’s activated, and it can be delivered to any UK address, so it’s perfect to send as a gift. Just make sure you get the ring size right!

Please see our guide to ring sizing

Warning once the ring is activated this cannot be reversed.

Can I return my Kerv ring if it doesn’t fit?

Yes, you can – as long as the ring and packaging are undamaged and you have not activated your ring.

Please repackage the box and ring carefully and return to:

Please email us at support@kerv.com and we will send you details of how to return your Kerv ring.

Can I return my Kerv ring if I change my mind?

Yes, but only within 28 days of receipt – and as long as the ring and packaging are undamaged and you have not activated your ring. You do not have to specify a reason if you don’t want to, but we would welcome your feedback.

Please email us at support@kerv.com and we will send you details of how to return your Kerv ring.

Can I cancel my order before my Kerv ring arrives?

Yes, you can – but only up until your ring is shipped – at which point we will send you a confirmation email.

If you want to return your ring you can, but only within 28 days of receipt – and as long as the ring and packaging are undamaged and you have not activated your ring. You do not have to specify a reason if you don’t want to, but we would welcome your feedback.

Please email us at support@kerv.com and we will send you details of how to return your Kerv ring.

What do I do if my Kerv ring doesn’t arrive?

Please email us at support@kerv.com with your order number and we’ll investigate what’s happened.

Kerv Wearables rebrand

Why are you changing your name / rebranding?

We’re changing our name because we've reached the end of a trademark dispute with an undisclosed company with a “similar” name, the result of which means we can’t complete the process of registering Kerv as a trademark.

Will I still be able to use my Kerv Ring?

The name change will have no impact on our service in any way, and you will be able to use Kerv Ring as usual, anywhere in the world that accepts Mastercard® contactless payments.

Will the ring design be changing?

We’ll be changing the logo on our next payment ring, but that's it – all its other unique design features and specifications will remain the same.

Can I exchange my Kerv Ring for one displaying the new brand logo?

Unfortunately, no. Your current Kerv Ring will be identical to the new ones – apart from the logo – and will still be welcomed anywhere that accepts Mastercard® contactless payments, even after the launch of the new branding.

What happens to the funds loaded onto my virtual prepaid Mastercard®?

Funds loaded onto your Kerv virtual prepaid Mastercard® will still be available to spend with your Kerv Ring, and with the forthcoming rings displaying the new logo.

What impact will the name change have on me?

Impact on the customer experience will be minimal; the main differences are that there will be a different email address for contacting support, and a different website address to log into your account, so you may need to update your bookmarks or saved contacts.

What is the new name?

We’re not revealing the new name just yet, but will be announcing it very soon.

Who can I talk to about the name change?

If you have any questions about our name change, please get in touch with us at support@kerv.com