[Waterproof ABS Material] The RFID key tag is made of high-quality ABS material, the shell is strong and durable, has good waterproof, shockproof and anti-corrosion performance, so that you can better use it in your daily life. After multiple processes, product quality can be well guaranteed. The red and blue colors give you more choices. [Comes with A Portable Key Ring] Each tag is equipped with a key ring, which can be hung on keys and other items for easy use and avoiding its loss. The volume of the key tag is 3.3x2.9x0.6cm, which is small in size and convenient to carry. It can be easily put in pockets and backpacks. The drop-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 EM 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 write-protected 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, Honeywell, Paradox, etc. The waterproof RFID key tag is suitable for 125KHZ card reader, and the reading distance is 0-10cm. [Good Helper for Access Control System] RFID key fob can be used in a variety of places, suitable for access control, hotel locks, employee attendance, school campus visits, identity recognition, security systems, parking lot 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 colour:blue, red