Glass windows are the easiest entry point for intruders. Over 90% of burglaries begin with broken glass. This Window Bug detects breaking glass. Millions of windows, throughout the world are protected with this ingenious Window Bug. The Window Bug uses a patented tuning fork mechanisim to detect glass breakage. The Window Bug is not affected by normal shock or vibration, so you won't have to worry about false alarms and costly service calls. Because it requires no voltage, the window Bug can't lose power or be frozen or shorted out. Protects up to 32 square feet. Adjustable operation for N/O or N/C circuit. Automatic reset. Peel and stick mounting. Provides good visible deterrent. The Window Bug is so effective that it is listed by Underwriters Laboratories for Primary Protection. White. MF021