An infrared motion detector functions by reacting to infrared light patterns radiating from objects in its field of view. This advanced six-LED model can detect people up to 16' away anywhere in its 90° viewing range. Its numerous features include automatic shut-off after 20, 60 or 90 seconds; you set the period you want. Similarly, you set the light level at which it turns on, avoiding needless activation during daylight hours. A second light-level control lets you adjust brightness to meet your minimum needs, again extending battery life.
The many places you can use one include closets, cupboards, nurseries, etc., but it is particularly useful to light stairways, since it requires no visible light to detect movement. Using one at the top and one at the bottom makes stairs much safer. A double-faced adhesive pad is included for attachment, or two screws can be used.
Each comes with four AAA batteries whose life depends on the light settings you use. It also has an off switch for periods when it's not needed. Battery life varies between 3 months for frequent use to 22 months if never activated. The base of the light measures about 3 3/8" in diameter. For indoor use only.