Features: Dual function,this door stopper security alarm can be a door stop alarm or a door stopper, when the alarm being triggered and it will keep the intruders outdoor from you, safe. if the door is installed very high and far from the ground,please put a soft thing under the door stopper.apartment house. Non-skid door stopper,the door stopper alarm in "off" statuse,it can be used as common damping rubber base door wedge,hold doors in open position,no any loud alarm sound. Easy to install, no wiring needed, just put battery in and switch the button on the back to “on” then it can works. the bottoms are made of synthetic rubber for keep the alarm from slipping. Lightweight and portable , portable doorstop alarm wedge ( include battery ) good for carrying when you are travelling or need spend a night at strange environment. Occassions,great for hotel door security devices traveling security door stopper doorstop safety tools for Home Specifications: Material:ABS+PC Color:Grey,White Package Includes: 1 Piece Door Stop Alarm note: Please allow 1-2cm errors due to manual measurement. Due to the difference betweeen different monitors,the picture may not reflect the actual color of the item.