[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, enabling it to be attached to keys and other items for easy use and to prevent loss. The key tag measures 3.3 x 2.9 x 0.6 cm, making it compact and portable. It can be easily carried in pockets or backpacks. Its ergonomic shape enhances daily usability. [TK4100 Chip] The RFID sensor ID card features a TK4100 chip with a working frequency of 125 kHz, compatible with standard ID access control devices. Each chip has a unique ID number stored within and printed on the back of the tag for security. [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, Radio, Cobra, APCiK, Indala, Isonas, etc. This waterproof RFID key tag works with 125 kHz card readers, with a reading distance of 0–10 cm. [Good Helper for Access Control System] Suitable for use in various applications including access control systems, hotel door locks, employee attendance, school campus visits, identity verification, security gates, parking lot access, and timekeeping systems. Ideal for any location requiring access management, such as offices, homes, schools, and residential communities. 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 differences may cause slight color variations between the image and the actual item. Measurement allows an error of +/- 1–3 cm.