Feature:1. Wireless Transmission: One host controls 16 sub machines, wireless transmission, 800 meters transmission distance, up to 998 sub machines can be connected, which can serve more customers.2. Wide Applications: Widely used in fast food restaurants, food courts, pizzerias, churches and auto shops or other places where there are many customers waiting to be served.3. 3 Vibration Modes: Using sophisticated production technology, with 3 vibration modes (vibration, beep, flashing), with excellent performance.4. Long Standby: Built in 250mAh lithium battery, equipped with upgraded chip, super long standby time of 20 hours.5. Deep Waterproof Design: Safe and deep waterproof design, waterproof and oil proof, no longer have to worry about overturning the soup.Specification:Item Type:Wireless Calling SystemMaterial: Plastic, ElectronicsHost:Transmission Frequency: 433MHzTransmit Power: 240mWNumber of Pager: 998Number of Charging Pager: 16Pager:Receiving Frequency: 433MHzReceive Sensitivity: -114dBmStandby Current: 30mAStandby Time: 20HTransmission Distance: More Than 800meters/874.9ydPrompt Method: Buzzer, Flashing LightBattery Type: Built in 250mAh Lithium Battery.Package List:1 x Wireless Calling System 16 x Restaurant Pager1 x Power1 x User Manual