This U.L. Listed door viewer is constructed of a solid brass housing, and it comes in a polished brass finish. The lens of this viewer is made of glass and it features a 200 degree angle of view. Viewer can be installed on doors from 1-3/8 in. thick to 2-1/8 in. thick, with a required 9/16 in. diameter hole for installation of viewer. Door viewer is designed to help keep you safe when answering your door and is ideal for day or night viewing with adequate exterior lighting. Easy to install and it is used by many. Inside viewer covers (not included with this item) prevent reversed visibility through door viewers from the exterior of the home, increasing the security and privacy of your home.