The Button unit does not require any power or battery operated. It is the self-generating design to activate the door bell to get the alert in-door. The indoor unit must plugged to the power source where can connect to Button unit with high sensitivity if it activated. Ease of installation. 
 
	
Ideal for use as an alarm for those who need quickly help and assistance, like the elderly, child, handicapped, pregnant women or sick, simply press the call button to alert the caregiver.
	
Long Range: Up to 280 meters range in open area, and using 16-bit encoding to eliminate interference from other devices, provides the performance to work actual anywhere in your home.
	
More Alert Options: 32 melody sounds to choose from, adjustable volume control
	
Convenient Placement: The waterproof transmitter can be worn as a pendant, or placed at bedside. Receiver can be wall mounted, placed on the desk or carried in caregiver's pocket.
 
Product size : Door Bell (100x55x26mm)
Button (65x65x44mm)
 
Weight : Door Bell (76g)
Button (50g)
 
Operation power : Door Bell (220V/50Hz) - two flat pins
Button (no power required)
 
Operation temperature : Door Bell (-10~+45 °C)
Button (-20~+60 °C)
 
Operation range : ≥ 50m (open field)
 
Operation frequency : 315M / 433M / 868MHz
 
Output power : 0.25W
 
Ringtone : 25
 
Ringtone volume : 80dB at 1m (max.) 
 
Ringer level : 3 levels adjustable
 
ES-HP-1809-1 one button + one host
ES-HP-1809-2 one button + two hosts
ES-HP-1809-3 two buttons + one hose
ES-HP-1809-4 one button + 3 hosts