Keychain Alarm with Motion Detector At about 2.5 inches tall this handy security device slips easily into a pocket or purse, but don't let its small size fool you The micro technology used in this alarm provides features that are similar to ones found in alarms 3 to 4 times its size It has a PIR motion detector, a 100dB personal alarm and a LED flashlight It is great for home, business, hotel and dorm rooms It can be used as a personal alarm for self defense, or set the motion detector to protect your home, apartment, or in a hotel to protect your valuables while you are out of your room The motion detector can also be used to prevent children from wondering into a dangerous area, such as a pool The alarm operates on 3 AG13/ LR44 button batteries that are included Specifications Dimensions: 2.625" x 1.375" x .875" Weight: 1 oz