Notice 1. This product cannot be used independently.2. Can be used with all the hosts in our store.3. If other stores meet the following conditions: A. Frequency: 433MHz B. IC: eV1527 C. Resistance: 330K Working voltage: DC3V (button battery)Standby current: 10uAWorking current: 15mAWorking temperature: -10 ~+50Emission distance: 120m(open field)Triggering distance: 25-35mmUnder voltage monitoring: 2.2±0.2VWireless encode mode: ev1527Emission frequency: 433MHzFields special designed with the SOS alarm door sensor Ensure greater security Induce the door/window open/close for 10mm range wireless transmit range can get to 80m.