Wireless Calling System. Feature:1. Each Pager Builtin Rechargeable Lithium Battery, Low Power Indicator and Charging Indicator 2. Support Learning Code Registration Mode, You Can Easily Add 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 Improve the Work Efficiency and Avoid the Guest Waiting in a Long Queue 5. External Antenna Support About 1000 Meters (3280ft) Working Distance in Open Area 6. Widely Used in Fast Food Restaurants, Food Courts, Pizzerias, Churches, Car Shops or Other Places Where Many Customers Are Waiting for Service Specification:Item Type: Wireless Calling SystemPager Frequency: 433MHz Receiving Sensitivity: -107dBm Decoder: Learning Code (AM) Standby Current: 10mA Working Current: 75mA (vibration) Menu 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 Want to Call: 1~999, then Press the "call" Key to Call. If the Wrong Number is Selected, Press the "clear" Key to Reselect the Number. Package List:1 X Keyboard Transmitter20 X Menu1 X Power Adapter1 X Antenna1 X User Manual . Your order will be shipped from abroad so please allow the necessary time of at least 14 work days for delivery due to ongoing delays in postal deliveries globally.