Color as shown Size: 6.6 x 6.6 x 2 cm Weight: 20 g 1. Easy to wear. 2. Resistant to the water. Each comes with key ring. included. 3. Works at a frequency of 125 kHz, can read and write. 4. Compatible with all RFID readers for access 5. Scope of delivery: 20 pieces of UID chip key fobs.