[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 well guaranteed. 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 in size and easy to carry. It can be conveniently stored in pockets or backpacks. The compact shape enhances usability for daily applications. [TK4100 Chip] The RFID sensor ID card uses the TK4100 chip, operating at a frequency of 125 kHz. It is 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 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. 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] This RFID key fob is suitable for various applications including access control, hotel door locks, employee attendance, school campus access, identity verification, security systems, parking access, and timekeeping systems. It can be used in any location requiring access control, 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 Card Tags Note: Light and display differences may cause slight variations between the color shown and the actual item. Measurement allows an error of +/- 1–3 cm.