# EM4305 Keyfob — 125 kHz Rewritable Access Fob

URL: https://proudtek.com/products/rfid-keyfobs/em4305-keyfob/
Source URL: https://proudtek.com/products/rfid-keyfobs/em4305-keyfob/
Generated: 2026-03-16T01:42:30.697Z
Kind: product
Publisher: Proud Tek Co., Limited
Author: Proud Tek Co., Limited
Credentials: ISO 9001:2015, ISO 14001:2015, RoHS Compliant, CE Marking, REACH Compliant
Image: https://proudtek.com/landing-images/em4305-keyfob.jpg
Image Alt: EM4305 rewritable 125 kHz RFID keyfob for access control

## Description
EM4305 keyfobs contain a rewritable 125 kHz LF RFID chip (ISO/IEC 18000-2 air-interface, 512-bit EEPROM, 100,000 write-cycle endurance, 32-bit password...

## Procurement Snapshot
- Best fit: Best for access control, parking, elevator, and membership credential projects.
- Key options: Form Factor: Compact keyfob form factor for handheld access credentials.
- Customization: Confirm artwork, encoding, material, chip, and finish requirements before quoting.
- Quote checklist: Reference EM4305 Keyfob — 125 kHz Rewritable Access Fob in your inquiry so the matching product page stays attached to the quote. Compact keyfob form factor for handheld access credentials. Share target chip or protocol, quantity,...

## Key Specs
- Form Factor: Compact keyfob form factor for handheld access credentials.

## FAQ
- Q: Can EM4305 keyfobs emulate HID proximity cards?
  A: Yes. EM4305 supports configurable data encoding and modulation that can emulate HID 26-bit (H10301) and other HID Prox formats. You program the facility code and card number into the EM4305 chip using a 125 kHz RFID writer, and the keyfob responds to HID ProxPoint readers as if it were a genuine HID card. Note: this emulation works for basic HID Prox protocols; HID iCLASS (13.56 MHz) requires a different chip.
- Q: How many times can the EM4305 be reprogrammed?
  A: The EM4305 EEPROM is rated for 100,000 write cycles. In a typical access control deployment where a keyfob is reprogrammed once per tenant turnover (1-2 times per year), the chip will outlast the physical keyfob housing by orders of magnitude. There is no practical rewrite limit for access control applications.
- Q: What is the MOQ and lead time?
  A: EM4305 keyfobs in standard ABS housing: MOQ 100, lead time 3-5 business days from stock. Custom-colored or silicone housing: MOQ 200, lead time 10-12 business days. Pre-programmed with your facility code or protocol emulation: add 1-2 business days to standard lead time. Volume pricing available at 500, 1,000 and 5,000+ quantities.
- Q: Should I be worried about EM4305 keyfob cloning?
  A: It depends on the threat model. 125 kHz LF chips — EM4100, EM4305, T5577 and HID Prox II — have no cryptographic authentication at the air interface. A consumer Proxmark 3 or Flipper Zero can read the ID in seconds. This is a property of LF Prox as a whole, not EM4305 specifically. For low-stakes applications (apartment common areas, storage unit access, gym lockers, tenant turnover reuse) this is the accepted trade-off for low cost and universal legacy compatibility. For enterprise access, hotel rooms, controlled substances or transit fare, migrate the deployment to HF 13.56 MHz with AES-128 (MIFARE Plus SE, DESFire EV3) or HID iCLASS SE / Seos.
- Q: Can EM4305 coexist with my HF 13.56 MHz reader on a dual-frequency migration?
  A: Yes. A dual-frequency keyfob carries both an EM4305 (or T5577) LF chip and a HF chip (typically MIFARE DESFire EV3 or an NTAG) in the same housing. The LF chip is read by existing 125 kHz proximity readers; the HF chip is read by new 13.56 MHz readers. Users keep the same fob through a multi-year reader-migration programme. See the [dual-frequency keyfob](/products/rfid-keyfobs/dual-frequency-key-fob/) SKU for specification details.

## Machine Routes
- JSON: https://proudtek.com/machine/products/rfid-keyfobs/em4305-keyfob.json
- Text: https://proudtek.com/machine/products/rfid-keyfobs/em4305-keyfob.txt