S184S Ultra Slim Door Guard - ***ects Vibration from Attempted Door Entry - High Output 100-110 dB Alarm - Alarm/Off/Chime Slide Switch Operation - Built-in Siren or Chime Modes - Alarm Activation Delay for Silent Setup - No Tool Installation - Simply hang on the door knob,even hock anywhere by unplug and plug the circular Hanger Loop - Ultra Slim Design - 3*1.5V AAA Batteries Operation (Included) - 6 Tone Alarm