Application: These products are widely used in access control system and related applications. Features: 1. Pre-programmed with a unique identification number in each keychain (this RFID card is read and rewritten.) 2. Frequency: 125 kHz 3. Standard: T5577 compatible 4. Contactless data transfer 5. Material: PVC 6. Reading distance: 5 cm ~ 12 cm 7. Size: 28 * 20.4 * 7.2 mm 8. Weight: 4.21 g / pc. 9. Waterproof