U.S. Patrol Alarm Security Wedge Bar Door Knob Jam NEW IN BOX Secures your home, dorm, office or hotel room from intruders with added security! As soon as the doorknob is touched, a sensor sounds the alarm like a powerful siren or barking dog to warn you or your neighbors that someone is trying to enter. An effective way to frighten away intruders. Easy no tool installation. Constructed of heavy gauge steel and uses one 9-volt battery(not included). For added security and protection Secures your home from intruders Alarm sound when door knob is touched Heavy gauge steel construction No installation required 2 1/2" Square bottom pivoting grip foot Pin-hole adjustable length Switch to Loud SIREN or Dog BARK Item Weight: 3 lbs. Shipping: FREE!! Can only ship within U.S. I cannot ship to PO Boxes.