[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 for reliable daily use. Produced through multiple manufacturing processes, the product quality is well assured. Available in red and blue colors for added choice. [Comes with a Portable Key Ring] Each tag includes 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 portable. It can be conveniently stored in pockets or backpacks. The rounded shape enhances usability for everyday carry. [TK4100 Chip] The RFID sensor ID chip is TK4100 type, operating at a frequency of 125 kHz. It is compatible with standard ID access devices and ID readers. 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 readers or encrypted readers such as Kaba, Radio, Cobra, HID, APCiK, Indala, Isonas, Paradox, 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] The 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 offices, homes, schools, residential communities, and other locations requiring access management. 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: The package includes only the items listed above. Other accessories are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement allowance is +/- 1–3 cm.