Description
125kHz RFID Key Fob — EM4100 / TK4100
Contactless RFID key fob listed for 125kHz EM4100 and TK4100-compatible readers. The source describes it as read-only: its identifier is fixed on the fob and can be registered in a compatible system. The identifier cannot be erased or rewritten.
- Chip type: EM4100 / TK4100, as listed
- Response frequency: 125kHz
- Dimensions: 43.7 × 30.5 × 5.3mm
- Operating temperature: −40 to +85°C
- Water resistance: described as waterproof in the source listing; no test rating is provided
- Available colours: select above
The listing names transport, parking, identification, attendance, ticketing and card payment as possible applications. Compatibility depends on the reader and access system. A fixed-ID 125kHz fob does not provide strong authentication by itself and should not be treated as a secure credential.
Select a colour above. For a rewritable version, see the EM4305 / TK5577 125kHz fob.









