Door Stop Alarm 1.cheap and high quality 2.wireless, easy to replace 3. ... :9V battery not includedVoltage:6VSpecial Feature:cheap, good quality, travel useProduct Usage:house door, hotel doorExport Market ... room, dorm room, apartment, or any room in your home.The unit is also equipped with a ... alarm. When traveling, just toss this lightweight unit in your luggage. Simply place the alarm behind any door ...