50pcs 125 kHz T5577 Rewritable Keychain Fob Tags Key benefits Ready for portable use: each tag includes a metal keychain ring for easy attachment to keys, backpacks, or lanyards, reducing the chance of loss and keeping tags accessible. Fully rewritable and blank by default: tags have no preprogrammed ID, so they must be written before they can be read. This makes them flexible for custom applications and secure control over which IDs are placed on the tag. Flexible encoding options: T5577 ID chip supports standard 125 kHz ID format and HID WG 125 kHz format, and can be customized to 26bit Prox format as needed. Broad compatibility: compatible with T5567, T5577, and EM4305 devices and works with HID systems and Flipper Zero for programming and testing. Durable construction: molded in ABS material with temperature resistance up to 190 degrees Fahrenheit, abrasion resistance, and dimensional stability for reliable daily use. Technical highlights Quantity: 50 pieces per pack Frequency: 125 kHz Chip: T5577 ID chip State out of the box: blank, not readable until programmed Writable formats: 125 kHz ID, HID WG 125 kHz, to 26bit Prox Compatible devices: T5567, T5577, EM4305, HID systems, Flipper Zero Not compatible with: ONITY systems, Proxmark3 RDV4, and Keysy rfid duplicator Practical applications Access control testing and development: program and test custom ID formats for door systems and RFID readers during installation and troubleshooting. item management: use as durable key fobs for team members, contractors, or event staff after programming unique IDs. Hobbies and hardware projects: integrate into DIY electronics, reader experiments, and device testing workflows using tools such as Flipper Zero. Important usage notes Tags are blank and cannot be read until an ID is written to them. Ensure your programmer supports T5577 encoding formats before attempting to read or duplicate. Confirm compatibility with your target reader or system. These tags do not work with ONITY systems, Proxmark3 RDV4, or Keysy rfid duplicator. This pack provides a practical, reusable set of 125 kHz T5577 key fobs for programming, testing, and everyday tagging tasks where rewritable IDs and portable form factor are required.