Usage Tips:[Waterproof ABS Material] The RFID key tag is made of ABS material, the shell is strong and durable, has good waterproof, shockproof and anti-corrosion performance. 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 put in pockets and backpacks. -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. standard ID access devices or ID . Each chip has its own ID, which is stored in the chip and on the back of the label to security.[Read Only & Easy to Read] The chip is write-protected and cannot be programmed! It does not support and is not UHF and encrypted , such as , Radio, Cobra, , APCiK, Indala, Isonas, , , 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 of , 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 where an access control system is needed, such as offices, homes, schools, communities, etc.Support: Read Only, Not Writable.Working Frequency:125KHZsize:29x33x6mmMaterial:ABScolour:blue, redPackage Contents:50 x 125Khz RFID Card Tags