[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, ensuring reliable use in various environments. After multiple manufacturing processes, product quality is well guaranteed. Available in red and blue colors for more choices.[Comes with a Portable Key Ring] Each tag comes with a key ring, allowing it to be easily attached 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, making it compact and easy to carry. It can be conveniently stored in pockets or backpacks. The ergonomic design enhances daily usability.[TK4100 Chip] The RFID sensor ID card uses the TK4100 chip with a working frequency of 125 kHz. It is compatible with standard ID access control devices. Each chip has a unique ID number permanently 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. 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 fob is suitable for various applications including access control, hotel door locks, employee attendance, school campus access, identity verification, security systems, parking lot entry, and timekeeping systems. It can be used in any location requiring an access control system, 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 color variations between the image and the actual item. Measurement allows an error of +/- 13 cm.