125KHz EM4100 RFID Cards & Keyfobs – 5 or 10 Pack
125KHz EM4100 RFID Cards & Keyfobs – 5 or 10 Pack
125KHz EM4100 Read-Only RFID Cards & Keyfobs — 5 or 10 Pack
Keep your access control or attendance system running smoothly with these reliable 125KHz EM4100 RFID cards and keyfobs. Each card arrives pre-programmed with a unique, factory-set ID number — no configuration required. Simply tap and go. Made in China.
Why Choose These RFID Cards?
- Instant Compatibility: Works with any standard 125KHz EM4100 / TK4100 reader — door access panels, time-attendance terminals, ticketing kiosks, and more.
- Fixed Unique ID: Each card is factory pre-programmed with a permanently assigned unique ID printed directly on the card face, ensuring consistent, reliable identification every time.
- Durable PVC Construction: Standard credit-card dimensions (85 × 54 × 0.88 mm) and lightweight at just 5 g ± 0.5 g. Resistant to water, dust, salt water, alcohol, oil, and common chemicals.
- Wide Operating Range: Tested read range of 2.5–10 cm (1–4 in.) for convenient tap-to-unlock use.
- Reliable Temperature Performance: Storage rated from −40 °C to +85 °C; operating range −25 °C to +70 °C.
- Multi-Detection Support: Compatible with multi-card detection readers for high-throughput environments.
- Value Pack: Available in 5-piece or 10-piece sets — perfect for outfitting a small office, rental property, or classroom.
Technical Specifications
| Chip Type | ID EM4100 / TK4100 |
| Operating Frequency | 125 KHz |
| Material | PVC |
| Card Size | 85 × 54 × 0.88 mm (standard credit card) |
| Weight | 5 g ± 0.5 g |
| Read Range | 2.5–10 cm (1–4 in.) |
| Card Type | Read-Only (factory pre-programmed, not rewritable) |
| Color | White |
| Storage Temperature | −40 °C to +85 °C |
| Operating Temperature | −25 °C to +70 °C |
| Country of Origin | Made in China |
⚠️ Important Note: These cards use the read-only EM4100 chip — the unique ID is permanently programmed and cannot be overwritten or changed. If you need rewritable tags, look for EM4305 or T5577 chip-based products instead.
Common Use Cases
- Office or apartment door access control systems
- Employee or student time-and-attendance tracking
- Gym, school, or club membership cards
- IoT smart home entry systems
- Ticketing and event management
- Replacement cards for existing 125KHz EM4100 installations
For broader context on RFID technology standards and security best practices, visit the NIST Guidelines for Securing RFID Systems.
Frequently Asked Questions
Q: Are these 125KHz EM4100 RFID cards rewritable?
A: No — these cards use the read-only EM4100 / TK4100 chip. Each card is factory pre-programmed with a unique, permanent ID that cannot be changed or overwritten. If you require rewritable RFID tags, you will need to choose cards with an EM4305 or T5577 chip instead.
Q: What access control readers are compatible with these RFID cards?
A: These cards are compatible with any standard 125KHz EM4100 or TK4100 reader, including most common door access control panels, time-attendance machines, and IoT entry systems. Always verify that your reader supports 125KHz EM4100 format before purchasing.
Q: How far away can the card be read?
A: The tested read range is approximately 2.5 to 10 cm (1 to 4 inches), depending on your specific reader's antenna strength. This is typical for contactless 125KHz proximity cards.
Q: Are these cards waterproof?
A: Yes. The PVC cards are waterproof and dustproof, and are resistant to immersion in salt water, alcohol, oil, and diluted chemicals, making them suitable for everyday indoor and outdoor use.