[Waterproof ABS Material] The RFID key fob is made of high-quality ABS material. The shell is strong and durable, with good waterproof, shockproof, and anti-corrosion performance, allowing you to use it better in your daily life. After several processes, the product quality can be well guaranteed. The red and blue colors give you more choices. [Comes with a Portable Keychain] Each tag is equipped with a keychain, which can be hung on keys and other items for easy use and to avoid loss. The volume of the key fob is 3.3x2.9x0.6cm, which is small in size and convenient to carry. It can be easily put in pockets and backpacks. The teardrop-shaped appearance makes it better for daily use. [TK4100 Chip] The type of RFID sensor ID card chip is TK4100, working frequency: 125Khz, you can choose the appropriate access card according to your needs. Compatible with standard ID access devices or ID readers. Each chip has its own ID, which is stored in the chip and printed on the back of the label to ensure security. [Read Only & Easy to Read] The chip is read-only and cannot be programmed! It does not support HID and is not compatible with UHF readers and encrypted readers, such as Kaba, Radio, Cobra, HID, APCiK, Indala, Isonas, Paradox, etc. The waterproof RFID key fob is suitable for 125KHZ card readers, and the reading distance is 0-10cm. [Good Helper for Access Control System] The RFID key fob can be used in a variety of places, suitable for access control, hotel locks, staff attendance, school visits, identity recognition, security systems, parking access, attendance systems, etc. It can be used in places where an access control system is needed, such as offices, homes, schools, communities, etc. Support: Read only, not writable. Working frequency: 125KHZ Size: 29x33x6mm Material: ABS Color: blue, red Package Contents: 50 x 125Khz RFID card tags Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowable measurement error is +/- 1-3 cm.