[Waterproof ABS Material] The RFID key tag is made of high-quality ABS material, which 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 well guaranteed. Available in red and blue colors for added choice.[Comes with a Portable Key Ring] Each tag comes with 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 in size and easy to carry. It can be conveniently stored in pockets or backpacks. Its compact shape enhances daily usability.[TK4100 Chip] The RFID sensor ID card chip is TK4100, operating at a frequency of 125 kHz, compatible with standard EM ID access devices. Each chip has a unique ID number stored in the chip and printed on the back of the tag for identification.[Read Only & Easy to Read] The chip is read-only and cannot be rewritten or programmed. It does not support HID and is not compatible with UHF or encrypted systems such as Radio, Cobra, HID, APCiK, Indala, or Isonas. The 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 fob can be used in various locations, suitable for access control systems, hotel locks, employee attendance, school campus access, identity recognition, security systems, parking lot access, and more. Ideal for use in 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 Card Tags Note: Light and display differences may cause slight variations in color between the image and the actual item. Measurement allows an error of +/- 13 cm.