Door Viewer 200 degree with Crystal lens. Standard style door viewer adds a useful security aspect to any door by enabling the user to see who is on the other side of the door before opening it. Extends to suit doors 35 - 55mm deep. For wider doors up to 100mm an extension sleeve (SWE1011) is available. The viewer gives a wider than average 200° angle of vision through a crystal lens. Certified to BS EN 1670. Comes with a 10 year mechanical guarantee and is Fire door rated. Part of the Steelworx range in Grade 316 Stainless Steel. Suitable for domestic and commercial use.