The Phidgets RFID Tag - Blue Key Fob is a passive, read-only device featuring a 40-bit unique ID that is preprogrammed and immutable. This blue key fob is designed to be conveniently attached to a keychain, ensuring ease of use and accessibility. It operates at a transmission frequency of 125 kHz and is compatible with all Phidget RFID controllers, making it a versatile choice for various applications. Constructed from durable ABS plastic, it is designed to withstand environmental factors, as indicated by its IP68 rating.