- RFID chip and compatibility Uses the original T5577 125 kHz chip. Supports TK4100 (EM4100) and EM4305 formats, enabling compatibility with common 125 kHz smart cards and devices. The design allows easy interaction with 125 kHz card systems. - Ring construction and material The ring combines an epoxy resin core with a zirconia ceramic outer shell for a stylish appearance and durable protection. The embedded smart chip is integrated within the ring, allowing practical use in everyday scenarios and on the go. - Ring size Available US ring sizes: 6, 7, 8, 9, 10, 11, 12. - Compatibility and use Compatible with TK4100 (EM4100) / EM4305 formats and other 125 kHz frequency cards. Designed to provide a compact wearable form factor for interacting with 125 kHz access systems. - Use scenarios - Authorized access control: wear the ring to present to 125 kHz readers at facilities you are authorized to access, providing a convenient alternative to a physical card. - Personal card backup: use as a portable backup for your own 125 kHz credentials, suitable for situations where a traditional card is unavailable. - Authorized security testing: perform legitimate, permission-based audits of access control systems using the ring as a test credential, under proper authorization.