RFID and NFC fobs for door access, apartment entry, business security, and time & attendance systems.
A security key fob uses Radio-Frequency Identification (RFID) or Near-Field Communication (NFC) to grant access to buildings, doors, elevators, and secure areas. The two most common standards are 125kHz (EM4100/HID Prox) — older and widely used — and 13.56MHz (MIFARE, HID iCLASS) — newer, more secure, and NFC-compatible. A basic 100-pack of 125kHz fobs costs under $30 on Amazon; a complete door entry system kit runs $60–$150.
125kHz vs 13.56MHz, cloning, and the best fobs for access control systems.
Bulk fob packs, complete door entry kits, and RFID readers — all on Amazon.
Security fobs contain a tiny passive RFID chip and antenna. When you hold the fob near a compatible reader, the reader's electromagnetic field powers the chip, which responds by broadcasting its unique ID. The reader checks the ID against a database and grants or denies access. Because the chip is passive (no battery), fobs last indefinitely — they only fail if the chip is physically damaged.
| Feature | 125kHz (Prox) | 13.56MHz (MIFARE / NFC) |
|---|---|---|
| Common Standards | EM4100, HID Prox, Indala | MIFARE Classic, MIFARE DESFire, HID iCLASS |
| Security Level | Low (ID only, easily cloned) | Higher (encrypted, challenge-response) |
| Cost (100-pack fobs) | ~$20–$30 | ~$40–$80 |
| NFC Phone Compatible | No | Yes |
| Best For | Low-risk residential access | Business, healthcare, high-security |