WRITABLE & REWRITABLE: This tag features a rewritable chip that supports writing in 125kHz ID format and HID WG 125kHz format. Suitable for creating and backing up access tags. FREQUENCY: 125kHz; Sensing Distance: 2.5 to 10 cm (1 to 4 inches); Data Storage Life: Up to 10 years. CHIPS: T5577 chip. This is a blank chip with no pre-programmed ID number. You must write an ID to the chip before it can be read. Ensure you have a compatible 125kHz RFID writer before purchase. MATERIAL: Built with high-quality copper coil and encased in durable ABS plastic. Waterproof and long-lasting. 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/copiers. Not compatible with ONITY systems or Proxmark3 RDV4 devices. CHIP: ATMEL T5577 (high-performance rewritable chip) WORKING MODE: Read-write capable – suitable for use with 125kHz RFID card copiers or duplicators STORAGE CAPACITY: 330 bits (264 free bits available) READING DISTANCE: 0 to 10 cm COLOR: Black MATERIAL: Plastic PACKAGE CONTENTS: 50 x Key Fob Note: Light reflection and display settings may cause slight color variations between the image and the actual item. Measurement allowance: +/- 1-3 cm.