[Waterproof ABS Material] The RFID key tag is made of high-quality ABS material. The shell is strong and durable, with 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 or other items for convenient use and to prevent loss. The key tag measures 3.3 x 2.9 x 0.6 cm, small and lightweight, easily fitting into pockets or backpacks. Its compact shape enhances daily usability.[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.[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 HID, Motorola, Mifare, or others. This waterproof RFID key tag works with 125 kHz card readers, with a reading distance of 010 cm.[Good Helper for Access Control System] This RFID key tag is suitable for use in access control systems, including hotel locks, employee attendance, school campus access, identity verification, parking lot entry, and more. Ideal for 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: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowed is +/- 13 cm.