... area(transimitter& reciver) Freqency: 315mhz/433mh Features:. DIY wireless installation, easy to operatioed, auto-alarm. it goes off ... 9VDC. siren index: 95db(test distance: 300mm, surrounding noise: 65db, standard voltage). sound frequency: 3.8kh2+10. wireless frquency: ... 433mhz or 315mhzInstallement and operation:. code preset by factroy, if no, please use tool to solder ...