Coaster Pager Specifications: Size: 102 x 102 x 1.6mm Frequency: 315MHz Power: built-in 3.7V lithium polymer battery, low battery indicator Color:red, light blue, dark Display: 4 digit red LED display 0.28 inches Model: sound, vibration, flashing Shell material: high quality poly-carbonate Keypad Transmitter Specifications: Size: 175 x 106 x 75 mm Weight: 366g Transmission power: 600mw Power supply: DC 12V 1A Transmission distance: 2000m (open area) Shell material: ABS plastic Support pager quantity: 9999 Color: black Note: Do not use one charger base to charge more than 10 coaster pager. You can add more coaster pager to the system as your business grows. If the pagers lose complete power, the system might have to be re-set, so you can turn off the pager or take in charge if dont use. Package Include: 1 x Keypad Transmitter 10 x Coaster Pager 1 x Antenna for Keypad Transmitter 1 x Charger Base 1 x Charger for Charger Base 1 x Charger for Keypad Transmitter 1 x English Manual