Wireless transmission, easy installation, ready to use after delivery.<br> Adopt waterproof design to avoid corrosion from tea, oil and water during work.<br> Built-in 300mAh large-capacity lithium battery, capable of 37 hours of standby.<br> Super resistant and anti-fall. All internal circuits are reinforced and more stable against drops.Can be used with 16 receivers, no need to worry about insufficient occasions.<br> Adaptive power supply: DC 12V/1A<br> Charging current: 20-50mA<br> Standby time: 200 hours<br> Number of code pairing: 998<br> Prompt mode: buzzer/vibration/light<br> Modulation mode: AM OOK<br> Working frequency: 433.92MHZ<br> Menu option:set prompt time:set buzzer speed<br> Set base ID/set extension number:set switch vibration<br> Transmission distance: 800 meters in open space<br> Voltage:AC220V<br> Plug Type:EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on<br> Note:Due to different production batches, there may be slight differences in products.<br> Colour:Black<br> Material:ABS<br> Package Contents:<br> 1 x Wireless Calling System<br> 16 x Receiver<br> Only the above package content, other products are not included.<br> Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.