WRITABLE & REWRITABLE: This tag features a rewritable chip that supports writing in 125kHz ID format and HID Wiegand 125kHz format. Ideal for creating and backing up access tags. FREQUENCY: 125kHz; Read Range: 2.5 to 10 cm (1 to 4 inches); Data Retention: Up to 10 years. CHIP: T5577 chip. This chip is not pre-programmed with an ID number. You must write data to the tag before use. Ensure you have a compatible 125kHz RFID writer before purchasing. MATERIAL: High-quality copper coil and ABS plastic casing. Waterproof design. Package includes 50 pieces. NOTE: These tags cannot be used directly with RFID locks. Data must be written using a 125kHz RFID card writer or copier. These are blank tags with no preloaded data. Compatible with most 125kHz RFID writers, but not compatible with ONITY systems or Proxmark3 RDV4 devices. CHIP TYPE: T5577 (commonly recognized as a reliable rewritable chip) WORKING MODE: Read-write capable – compatible with 125kHz RFID card copiers and duplicators STORAGE CAPACITY: 330 bits (264 free bits available) READ RANGE: 0 - 10 cm NOTE: Must be programmed before use. No data is pre-written on the chip. COLOR: Black MATERIAL: Plastic PACKAGE CONTENTS: 50 x Key Fob Note: Other accessories are not included. Note: Lighting effects and display settings may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3 cm.