... area(transimitter& reciver) Freqency: 315mhz/433mh Features:. DIY wireless installation, easy to operatioed, auto-alarm. it goes ... with ourdoor dield ,home farm, business stroe,public plaza security. widely used for residential area, office, workshop, school, ... 65db, standard voltage). sound frequency: 3.8kh2+10. wireless frquency: 433mhz or 315mhzInstallement and operation:. code preset by ...