Wedge-shaped portable alarm system emits a powerful, ear-piercing 120dB alarm when placed at the base of any door and the door is opened. Provides security and peace of mind at home, in dorm rooms and hotels when travelling. Adjustable sensitivity. Compact design for discreet positioning at entrance points. Requires 1 x 9V (PP3) battery. Wedge-shaped portable alarm system emits a powerful, ear-piercing 120dB alarm when placed at the base of any door and the door is opened. Provides security and peace of mind at home, in dorm rooms and hotels when travelling. Adjustable sensitivity. Compact design for discreet positioning at entrance points. Requires 1 x 9V (PP3) battery.