K Ring Review

Update: As of July 2018, Kerv Wearables became K Wearables (see our post here to learn why). We have changed the content of this page to reflect the new brand. We’ve not altered any other part of the review, as the functionality is exactly the same.

Now, on to the review!

The K Ring is the world’s first contactless payment ring. This innovative Smart Ring leads the way in the next-generation wearables market when it comes to payment devices. K Ring uses similar technology to many of the contactless payment cards on the market today but obviously has one difference – it is an attractive, comfortable wearable Smart Ring.

What can it do?

K Ring paymentK Ring can be used to make a payment anywhere in the world that accepts standard contactless credit, debit and prepaid card payments. Anywhere you see a Mastercard contactless payment system in place, a K Ring can be used. Stores, restaurants, bars, cinemas, taxis – you name it, there are almost 40 million retail locations worldwide to choose from. If you see the contactless payment system, it also accepts the K Ring.

Oh and the K Ring can also be used to facilitate one-touch access to some public transport networks. At the moment the only public transport network supported is the tFL (Transport for London) network. Great news for Londoners! We’ll update you as more transport partners are brought onboard the K platform.


In effect your K Ring is a virtual prepaid Mastercard and meets strict security rules of the FCA (Financial Conduct Authority), a financial regulatory body in the United Kingdom.

k ringK Wearables 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

To use the K Ring for contactless payment, you will need the K Wearables prepaid Mastercard. This can be used in-app, online, or over the telephone (because obviously you cannot use your K Ring in all situations).

You can attach up to 3 rings to your K Wearbles Prepaid Mastercard, and they will all be sharing the funds.

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


We think that this Smart Ring is one of the most stylish on the market. It does not need to hold as much technology “under the hood” as other rings given it is solely a payment facilitator. The styling is sleek, minimalistic and given there are 14 colour combinations, there is a combination for everyone.

Not sure of your ring size. No problem, K Ring can send you a measuring tape to confirm your exact sizing before you order.

Design choices

k ringWe think that the K Ring looks pretty slick. In fact, it is one of the most appealing Smart Rings on the market. It’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

The K 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.”

Buy Smart Ring Summary

We’ve been watching the K Ring for a while now. At times it looked as though it might not make it onto market but we are very pleased to see the Kerv ring make its debut as another option for wearables enthusiasts.

Give it is a payment device the obvious concern for potential buyers is the security of the ring itself given it will be connected to your prepaid Mastercard. Transactions with K Wearables over the Mastercard network are just as secure as using your chip and PIN on your physical Mastercard.

There are a few measures in place to ease your mind on this front, namely:

  1. You’ll need to activate your K Ring before you can use it to make a payment. Until your ring is activated, it is not associated with your K Wearables Account and is completely inert. Once you have activated your ring this cannot be reversed.
  2. As is the case for your Chip and PIN on your current payment cards, your ring must be within very close proximity to a contactless reader, within 4cm of a contactless payment terminal to be exact
  3. Your hand must be in the “Transmission Ready Position” to avoid any unintended transfer of data or funds. Check out the video from K Wearbles that shows you have to use it properly:
  4. Your transactional data is always encrypted and because K Ring never leaves your finger, the risk of cloning or theft is significantly reduced.
  5. Transactions must be initiated by the retailer, which means that the contactless card reader inside the ring is inactive until payment is specifically requested.

Unlike a majority of the other Smart Rings on the market, the K Ring does not need to be charged nor does it need to be paired with your smartphone.


In terms of market product comparisons, the K Ring can only be compared to the NFC Ring which also has a capability to make contactless payments. Currently NFC Rings are available for purchase worldwide unlike the K Ring which is currently only available in the UK.

The materials that make up the Smart Ring seem pretty durable although the manufacturer suggested that it can still be damaged “if dropped on hard surfaces, or a significant force is applied to it.”

Mass Appeal

This ring will appeal to those looking to streamline the way they pay anywhere that accepts Mastercard contactless payments. Sick of carrying your purse or wallet wherever they go? Enter the K Ring. We can also see a great application for those with kids/teenagers. Off to the movies with friends or to shop with YOUR money?  Simply pop some money into the connected to your K Wearables Prepaid Mastercard and off they go. No more surprises on your credit card with an OTT shopping spree or shouting popcorn…for the whole cinema!!


In relation to being able to purchase the K Ring there is good news and there is bad news. The good news is that if you live in the UK, you can buy yourself a K Ring right now. Yay for you!! The bad news? If you live anywhere else, the K Ring is not yet available. K Wearables have confirmed that they will make the ring available across Europe in the coming months. Buy Smart Rings will keep you across any changes on this front as they are communicated.

There is currently a limit placed on the amount of money you can use with a contactless device. That limit is 30 pounds in the UK which means you will not be able to make larger purchases with your K Ring. This limit does not apply however to online or in-app purchases made with your K Wearables Prepaid Mastercard. Whilst the K Ring can only currently be purchased in the UK, the ring can be used worldwide wherever there is a Mastercard contactless payment system in place.

Compatible apps

To activate your ring you need to first register for a K Wearables Prepaid Mastercard which can be completed in a matter of minutes. For extra peace of mind, you can switch your K Ring on and off, set restrictions and get live transaction alerts – all managed within your K Wearables Account.

Stand Alone?

That’s right, the K Ring doesn’t need to be paired with your smartphone or another device. This is pretty useful and also has the added benefit of not adding battery drain to your smartphone use. Whilst Smart Rings aren’t that thirsty in terms of battery consumption, the less the better.


There is not a lot to the unboxing process for the K Ring given it does not require a charging box or any additional accessories. This will make it a very minimalistic unboxing moment!

Product Details

Compatibility  n/a as the K Ring doesn’t require pairing
Bluetooth Bluetooth Low Energy
Materials Zirconia ceramic (ZrO2)
Nickel free Yes
Dimensions See the K Wearables size guide here.
Sizings See the K Wearables size guide here.
Waterproof Yes
Returns Via myKring website
Expected battery life Does not require charging, but has a 3 year expiry
Battery life span  n/a
Warranty  Contact K Wearables

8 responses to “K Ring Review”

  1. Mine hardly ever works. I think it’s useless. I could be using it wrong but have many ways can you present the a ring to a payment terminal. I bought mine mainly to use on the tube in London so I would have to faff around with my Oyster or card. I’m not confident enough to use it though. Im certain with such a low level of acceptance and reliability, I’d be strung up by other impatient passengers on my first journey. Summary: Great idea….shockingly poor execution.

    • I’ve had mine for a year and it has pretty much worked every time. However there is one type of terminal that I have come across a few times (mostly in Nando’s) and it never seems to work on those. The terminals it hasn’t worked on have all been that same type (or at least looked the same). One thing I have found is that you just have to wait a couple of seconds until you see the contactless ready symbol on the terminal. If you present the ring before that it asks to present again and then does not work. Just a few minor things I have found however otherwise absolutely love mine. I did sadly crack it though and there is a tiny little hairline crack, it allows me to see the inside of the ring if I stretch it out though which is pretty cool!

      • Some brands of terminals are problematic with most Bluetooth devices, so I imagine Nando’s just happen to use one of those brands. Sorry to hear about the crack though!

  2. Cheers for the useful feedback Mark. I’ll save my money.
    Looked temping but not fit for purpose

  3. I bought one for my husband for Christmas. Delivery was quicker than expected however, the ring way poorer than hoped for. It hardly ever works when trying to pay for something, sometimes you need to take the ring off to place it on the contactless machine in a certain way (You could have used your card in this time)
    After less than 30 days of NORMAL use, the ring cracked and was sent back to K Ring.

    My husband then emailed K Ring, who advised him to send the ring to them and leave the money on the account. Even though the account, with money in, is in my husbands name, K Ring emailed me to confirm they had received it. This is very poor CS as what if I had deceised or separated with my husband within this time?

    Since the confirmation of receiving the ring, my husband has emailed them multiple times with no response. They have no telephone number, to query what is going on with his ring. After 2 weeks of emails to K Ring and a complaint raised, they finally respond – “The average turn around for the ring is 2 weeks.” No apology, the complaint had been totally dismissed. No confirmation of the complaint summary letter either, so my husband took the matter to the ombudsman who told him to wait 8 weeks, as expected.

    The point is, K Ring are supposedly regulated by the FCa however, dismissing all major requirements and especially TCF. My husband could be a vulnerable customer or he could have had hundreds on the accounts.

    considering K Ring is a bank, I would not recommend using their services, purely because the customer service is appalling.

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