The GE Motion Sensing Alarm Kit is easy to install, requires no wiring and sounds a 120-dB alarm when motion is detected within its 70 degree angle and 20 foot range. A 4-digit keypad operates the alarm. A delay feature allows you to enter and leave without activating the alarm. It also has a chime mode and a low battery indicator. Included are three window security stickers and one yard sign to help deter intruders. The GE Motion Sensing Alarm Kit can be used free standing or wall mounted with the included bracket. Requires 3 AAA batteries (not included). It can also be powered by an a DC 4.5 volt power adapter (not included). For example, Radio Shack power adapter model number 273-1765 with tip number 273-1708 will power the unit. Setting the correct tip polarity is important to prevent damage to the device or adaptor. Read the directions carefully for proper usage. If you need assistance, you can take the device to Radio Shack. The GE Motion Sensing Alarm measures 5 inches x 2 and one half inches by 1 inch. The yard sign measures 16 and one half inches x 10 inches. The window stickers measure 3 inches by 1 and three-quarter inches.