This decorative door knocker and viewer is constructed of diecast materials and comes in a polished brass finish. Its vintage design extends a total of 5-1/2 inch tall and features a 160 degree angle of view. This door knocker and viewer can be installed on doors from 1-3/8 inch thick to 1-3/4 inch thick, with a required 9/16 inch inside diameter hole for installation of viewer. The integrated door viewer within this door knocker is designed to help keep you safe when answering your door and is ideal for day or night viewing with adequate exterior lighting. This door knocker and viewer is easy to install and it is used by many. See Prime-Line part S 4793 for a door viewer inside cover. 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.