125KHz Read and Write EM4305 LF Keyfob is made of ABS material with rfid chip and antenna . It will be durable and injection ABS case then sealing rfid chip under ultrasonic machine without any space sideview so that you can use them in out-door harsh environment and waterproof .It is fully compliant with ISO11784/11785 standard protocol .EM4305 low frequency 125khz rfid chip is 512 bit EEPROM organized in 16 words of 32 bit and 32 bit uniqueidentifier ( UID ) .It has function of reading and writting than mostly of read only low frequency chip .Widely uses in animal identification , waste management ,access control and industrial .etc .