I have used AirTags for several years to track my car keys, wallet and other valuables, and these have reassured me both when travelling, or when I can't remember where I left my keys. However, AirTags are somewhat bulky, for example to slip in a wallet. The Rhinokey Smartcard slides into my wallet, just like a credit card, or beneath the fabric lining of my boxes of musical instruments. Rhinokey take the technology of the AirTag in a more convenient formfactor.