Fangrui Product Details Wireless Transmission, Easy Installation, Ready To Use After Delivery. Adopt Waterproof Design To Avoid Corrosion From Tea, Oil And Water During Work. Built-in 300mah Large-capacity Lithium Battery, Capable Of 37 Hours Of Standby. 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. Adaptive Power Supply: Dc 12v/1a Charging Current: 20-50ma Standby Time: 200 Hours Number Of Code Pairing: 998 Prompt Mode: Buzzer/vibration/light Modulation Mode: Am Ook Working Frequency: 433.92mhz Menu Option:set Prompt Time:set Buzzer Speed Set Base Id/set Extension Number:set Switch Vibration Transmission Distance: 800 Meters In Open Space Voltage:ac220v Plug Type:eu Plug,it Applies To Indonesia, Germany, France, Spain, Italy And So On Note:due To Different Production Batches, There May Be Slight Differences In Products. Colour:black Material:abs Package Contents: 1 X Wireless Calling System 16 X