WRITABLE REWRITABLE It is a rewritable chip, and it can write in 125khz id format and H ID WG 125khz format. Suitable for making new and backup tags. FREQUENCY 125kHz Sensing distance 2.5 to 10cm Data storage time 10 years. CHIPS T5577 Chips, it has no preprogrammed id number, so you need to write the id on it before reading, so make sure you have the printer before buying it. MATERIAL High quality copper coil inside. The material of the housing is ABS plastic. Waterproof . The package contains 50pcs. NOTE You cant add them directly to RFID lock. You need to write data into them with a 125kHz RFID card reader before use. They are blank tags, no data inside. Can be written by 125KHz RFID printercopier, DOES NOT WORK WITH ONITY SYSTEM and Promark3 RDV4. Chip T5577 The best rewritable chip Working mode Readwrite modes Can be used in 125KHz RFID card copierduplicator Storage capacity 330 bit 264 bit free availability Reading distance is 0 10cm Note Please note that you need to write the ID on it before reading, it is a chip. Color Black Material Plastic Package Contents 50 Key Tag The above package content only, other products are not included. Note Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 13 cm.