1. working distance adjustable;
2. no interference with other alarm users;
3. transmitter un-removable by carrier without tool;
4.  if the transmitter wristband is damaged or cut, the receiver will sound warning alarm;
5. the batteries can be replaced inside the receiver and transmitter;
6. available to turn off/on receiver and transmitter;
7. receiver & transmitter have low battery warning ;
8. receiver has reset function;
9. light, voice & vibrating warning simultaneously;
10. receiver and transmitter have working indicator;
11.  transmitter is waterproof;
12.  receiver can locate the transmitter;
13.  Information function