DOOR STOPPER SECURITY ALARM the door stopper alarm in "on" status,when door pressure is applied,the door alarm will be triggered while make extremely loud 120db alarm,helps wake/alert homeowner or renter, helps deter intruder and possibly notifies neighbors,security protection. NON-SKID DOOR STOPPER the door stopper alarm in "off" status,it can be used as common damping rubber base door wedge,hold door in open position,no any loud alarm sound. EASY INSTALLATION no wiring needed; battery-operated (requires 1x9V battery,not included);place it under the door,the gap bewteen the bottom of the door and the floor should be 10mm(0.38 in) to 35mm(1.35 in),it can not slide on tile when door opens,smooth floor can try to use H-type sensitivity,vibration-sensing alarm. 3 SENSITIVITY LEVELS Low - Medium - High,with an adjustable sensitivity switch on the side;H level is the most sensitive level that vibration will trigger an alarm;please note when the alarm sound gradually becomes smaller,it means to replace the new battery. PORTABLE DOOR STOPPER ALARM package include 3 door alarms,each weight about 120g;easy to carry;alarm loud 120db to protect you;great for travel;ideal for bedrooms, hotels, apartments, dorm rooms, front doors, etc;peace of mind when traveling or working alone. Product Description ZZRUI Upgraded Door Stopper Security Alarm Wedge,Portable 120 Loud Entrance Alert Door Stop Alarm for Travel Home Apartment House Easy and Practical DIY Installation Install the battery,place it under the door,the door stopper alarm in "on" status,when door pressure is applied,the door alarm will be triggered while make extremely loud 120db alarm;the door stopper alarm in "off" status,it can be used as common damping rubber base door wedge,hold door in open position,no any loud alarm sound. The Door Stop Alarm offers a practical, inexpensive means to help protect yourself and safeguard your belongings. The Dorm Stop Alarm is battery operated with a built in siren. It is portable and doesnt require any wiring or complicated installation making it ideal for bedrooms, apartments and dorms as well as for hotel rooms when traveling. Pressure from an inward opening door sets off a 120 dB alarm that is likely to startle and scare off an intruder and wake you. Also, the anti-skid pad helps prevent door from opening. Wide Range of Applications Great for travel;ideal for bedrooms, hotels, apartments, dorm rooms, front doors, etc;peace of mind when traveling or working alone. Read more EASY INSTALLATION no wiring needed; battery-operated (requires 1x9V battery,not included),push the turn on button in the back of the door stop alarm into working status;place it under the door,the gap bewteen the bottom of the door and the floor should be 10mm(0.38 in) to 35mm(1.35 in),it can not slide on tile or smooth hardwood door when door opens,smooth floor can try to use H-type sensitivity,vibration-sensing alarm. Read more