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 System Material: Plastic, Electronics Host: Transmission Frequency: 433MHz Transmit Power: 240mW Number of Pager: 998 Number of Charging Pager: 16 Pager: Receiving Frequency: 433MHz Receive Sensitivity: -114dBm Standby Current: 30mA Standby Time: 20H Transmission Distance: More Than 800meters/874.9yd Prompt Method: Buzzer, Flashing Light Battery Type: Built in 250mAh Lithium Battery. Package List: 1 x Wireless Calling System 16 x Restaurant Pager1 x Power1 x User Manual