It widely used for access control, hotel locks, staff attendance and school campus access and payment control, parking lot entry, identification and security systems,  transportation payment, municipal and ancillary service payment.Commonly100pcs/pack. FEATURES: Operation frequency: 125Khz/TK4100 Compatible with all RFID reader to gain access Detecting distance: 0-8cm Each token pre-programmed with unique ID which is printed on it Key ring included Multiple colors and size are available.