This door viewer is constructed of a diecast housing, and the solid brass end caps come in a polished finish. The lens of this viewer is made of glass and it features a 130 degree angle of view. This viewer can be installed on doors from 1-3/4 in. thick to 2-3/8 in. thick, with a required 1 in. diameter hole for installation of viewer. Door viewers like these are designed to help keep you safe when answering your door and is ideal for day or night viewing with adequate exterior lighting. Installation of this viewer is easy, and it is used by many.