The keypad call can send 999 different codes by combination from digital 0- 9. One transmitter can connect up to 999 coasters. Each mode is accompanied by the LED flash--- Vibration/Buzzer/ Vibration and Buzzer. Built-in external antenna, working distance is about 800m. The maximize button can avoid the wrong operation effectively.
High quality plastic supports waterproof and oil-proof. Size:80 x 73 x 15mm / 3.1 x 2.9 x 0.6in;Weight:59g / 0.13lb ;Built in DC3.7V rechargeable. With full charge it can be used for at least 72 hours standby, 36 hours in use. Independent storage memory avoiding data lost.
Working voltage: DC 5V power adapter.