[Waterproof ABS Material] The RFID key tag is made of high-quality ABS material, with a strong and durable shell that offers good waterproof, shockproof, and anti-corrosion performance, allowing for reliable use in various environments. After multiple manufacturing processes, product quality is ensured. Available in red and blue colors for added choice.[Comes with a Portable Key Ring] Each tag includes a key ring, making it easy to attach to keys and other items for convenient use and to prevent loss. The key tag measures 3.3 x 2.9 x 0.6 cm, is compact, and easy to carry, fitting conveniently into pockets or backpacks. Its rounded shape enhances usability for daily applications.[TK4100 Chip] The RFID sensor ID card uses the TK4100 chip, operating at a frequency of 125 kHz, compatible with standard ID access control systems. Each chip has a unique ID number permanently stored and printed on the back for identification. Works with standard 125 kHz readers.[Read Only & Easy to Read] The chip is read-only and cannot be rewritten or programmed. It does not support UHF or encrypted formats such as Mifare, HID, Indala, Isonas, or others. This waterproof RFID key tag is designed for use with 125 kHz card readers, with an effective reading distance of 010 cm.[Good Helper for Access Control System] Suitable for various access control applications including door locks, employee attendance, school campus access, identity verification, parking access, and more. Ideal for use in offices, homes, schools, residential communities, and hotels.Support: Read Only, Not Writable Working Frequency: 125 kHz Size: 29 x 33 x 6 mm Material: ABS Color: Blue, Red Package Contents: 50 x 125 kHz RFID Key Tags Note: Light and display settings may cause slight color variations between the image and the actual item. Measurement error allowed is +/- 13 cm.