WRITABLEWRITEABLE It is a rewritable chip, and it can write in 125khz id format and H ID WG 125khz format. Suitable for making and backing up tags.FREQUENCY 125kHz Sensing distance 2.5 to 10 cm Data storage time 10 years.CHIPS T5577 Chips, it has no preprogrammed id number, so you need to write idt on it before reading, so make sure you have the printer before you buy it.MATERIAL High quality copper coil inside. Housing material is ABS plastic. WaterproofThe package contains 50 pcs.NOTE You cannot add them directly to RFID locks. You must 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 reader copier, DOES NOT WORK WITH ONITY SYSTEM and Promark3 RDV4.chip T5577 The best rewritable chipWork mode Readwrite modesCan be used in 125KHz RFID card copier/replicatorStorage capacity 330 bit 264 bit free availabilityThe reading distance is 010cmNote Please note that you must write idt on it before reading, it is a chip.Color BlackMaterial plasticPackage contents50Key tagOnly the above package contents, other products are not included.Note Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowable measurement error is13cm.