A U-Key is an implementation of the MIFARE RFID chip, encased in a plastic key style housing. It is used as a prepayment system on vending machines[1] and for some self-service diving air compressors[2] in Switzerland, and they will be most likely made by Selecta (company).
![](http://up.wiki.x.io/wikipedia/commons/thumb/1/19/U-key.jpg/220px-U-key.jpg)
References
edit- ^ "U-KEY system features". Microtronic. Retrieved 24 Feb 2019.
- ^ "Schweizer Luftverbund".