See All PV18-180 Panaramic Full Dome Plexiglas Security Mirror, 180 Degree Viewing Angle, 18' Diameter (Pack of 1)Category: 180 MirrorSize:18 inches The See All Panaramic half dome Plexiglas security mirror is an acrylic dome mirror that mounts on a wall and reflects a 180 degree angle image for an overhead view of 3-way intersections, and helps a person see around obstacles for safety, or monitor a wide area for efficient surveillance. Acrylic is shatter resistant, weighs less than glass, and reflects a clear, bright image. The mirror comes with wall-mounting hardware for convenient installation. SpecificationsModelSize and CoveragePV18-18018' diameter, covers areas up to 150 sq. ft.PV26-18026' diameter, covers areas up to 200 sq. ft.PV32-18030' diameter, covers areas up to 225 sq. ft.PV36-18036' diameter, covers areas up to 250 sq. ft.PV48-18048' diameter, covers areas up to 400 sq. ft. Safety mirrors are used to help increase visibility in a variety of locations; for example, in hallway intersections and sharp turns, and in driveways and loading docks where drivers have to back up or enter traffic. Safety mirrors are sometimes called security mirrors, and they can be used to extend the view of security personnel, or to help monitor factory workers and automated processes to improve quality control and productivity. For convex mirrors, objects will appear to be further away than they are, and will be easier to see in a larger mirror. Depending on visibility conditions and the viewer's eyesight, objects will usually be recognizable within about 1 ft. of distance (including distance from eye to mirror, and from mirror to object) for each inch in mirror diameter. See All Industries manufactures safety and security mirrors. The company, founded in 1958, is headquartered in Chicago, IL.