Wearable technology company Kerv has developed an NFC-based contactless payment ring that links to a deposit account at PSI-Pay, a Mastercard-licensed payment institution. Users are also given the choice of a plastic prepaid Mastercard card for in-store purchases or a virtual Mastercard number if they want only an online payment option. The Mastercard products can be funded via PayPal, a bank transfer, or a credit or debit card. Kerv rings are made of zirconia ceramic, which does not interfere with the electromagnetic field that powers their contactless functionality. Available in black or ...