panic buttonFunctions Features:Microcomputer intelligent control and steady performance;High capacity rechargeable Li-ion battery,Website:http://www.home-security-life.com, long service life.Send emergency signal to alarm host to activate emergency alarm, generally set as 24-hour Emergency Zone.Specifications: 1.Power supply: 3.7V/200mAh2.Charging time: greater than or equal to 12 h3.Emission distance: greater than or equal to 150 meters (in open air)4.Full loaded battery work time: less than or equal to 3 years