Feature: 1. Each pager builtin rechargeable lithium battery, low power indicator and charging indicator 2. Support learning code registration mode, you can easily up to 999 pagers 3. Have two remind mode of vibration and buzzer, each mode is accompanied by LED flashing 4. Equipped with up to 20 battery charging slots, greatly the work efficiency and avoid the in a long queue 5. External antenna support about 1000 (3280ft) working distance in open area. Widely used in fast food restaurants, food courts, pizzerias, churches, car shops or other where many customers are for service Specification: Item Type: Wireless calling system Pager Frequency: 433MHz Receiving Sensitivity: -107dBm Decoder: Learning code (AM) Standby Current: 10mA Working Current: 75mA (vibration) Battery Capacity: Built-in 200mAh rechargeable lithium battery Charging Voltage: DC 5V Keyboard Call Button: Frequency: 433MHz Standby Current: 24 mA Transmission Current: 100 mA Working Voltage: DC 5V / 2.5A power adapter Key Function: Power/Reset: Long press for 3 seconds to turn on/off; short press to reset to standby Code Recording: Long press for 3 seconds to enter the code recording state Mode: Switch the remind mode, dial up for vibration mode; dial down for vibration + buzzer mode Keyboard: Press 0~9 digits to select the number you to call: 1~999, then press the "call" key to call. If the wrong number is , press the "clear" key to reselect the number. Plug Type:US Plug,it applies to Canada, ,Mexico, Thailand, the , the Philippines,Taiwan and so on. Voltage: AC110V Material: plastic colour: black Package Contents: 1 x Transmitter 20 x Receivers 1 Adapter 1 x English Manual Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.