... DIY. Smart and good-looking.Wireless burglar alarm system with telephone alarm function DESCRIPTION:DIY, Wireless installation, Easy-to-operated. ... business store, public plaza security and so on intelligent home function. Widely used forsignal home, residential area ... , indoor: 30~50m, (depend on the surrounding environment and wireless interference)4. Standby current: < 20mA5. Alarm volume: internal ...