Features: 1.Wireless signal transmission stable and long distance, highly anti?interference and system signal range covers over 600 feet in open area. 2.Fashionable appearance and novel design, easy and convenient to move. Displayable time "year, month and day". 3.The display receiver supports 400 pagers, one?button or 4?button pagersWord of call button is selectable, single or list display mode. 4.30 levels adjustable volume, and you can name the call button starting with ABCDEF, providing more convenience. 5.Suitable for restaurant, nursing home, cafes, supermarkets, hotel, hospital wards, emergency center, banks, schools, factories, construction sites. specification:Item Type: Wireless Calling System Material: ABS Display Receiver Parameters: Operating Frequency 433.92MHz Working Voltage: DC5V Working Current: 100mA10mA Receiving Sensitivity: 105dB Decoding: Learning the Code Waterproof Rating: IPX4 Working Temperature: -20~ 60 Button Transmitter Parameters: Operating Frequency 433.92MHz Battery: Two Built-in CR2032 Lithium Batteries (included) Battery Capacity: 80mAh Emission Current: 10mA3mA Standby Current: 200m / 656ft Keys: A Million Times Waterproof Rating: IPX4 Working Temperature: -20~ 55 Four Keys: Call, Check Out, Place an Order, Cancel Voltage: 110-240V PackageList:1 x Wireless Receiver 10 x Call Buttons 10 x Stickers 1 x Manual 1 x Adapter NoteTransmitter shipped with built?in battery