This is a pack of 50 blank, writable RFID key fob tags. Each tag features a high-quality T5577 chip, which is a rewritable 125kHz RFID chip. These tags are ideal for creating custom access control tags, backups, or for general RFID applications. **Key Features:** * **Writable & Rewritable:** The T5577 chip can be written and rewritten multiple times. It supports writing in standard 125kHz ID format and H ID WG 125kHz format. * **Blank for Programming:** These tags come completely blank with no pre-programmed ID. You **must** use a compatible 125kHz RFID writer/duplicator to program them before they can be read or used. * **Reliable Performance:** Features a sensing/reading distance of up to 10 cm (4 inches). The internal high-quality copper coil ensures consistent performance. The ABS plastic casing is durable and waterproof. * **Technical Specifications:** Frequency: 125kHz. Data Storage Life: 10 years. Storage Capacity: 330 bits (264 bits free). **Important Notes:** * A compatible 125kHz RFID writer/copier/duplicator is **required** to program these tags; they cannot be added directly to RFID locks without first being written. * These tags are **not compatible** with the Onity system or the Proxmark3 RDV4. * Package includes 50 black plastic key fob tags only. Other products are not included. * Please allow for slight color variations due to photography and monitor displays.