The Lockwood Door Viewer is designed for ease of view outside, whilst remaining safely secure behind your closed door. Features: - Optical glass lens allowing a clear 160° viewing angle - Brass body - Suits door thickness of 32 to 51mm - Requires a 13mm drill hole - Fire rated up to 4 hours in accordance with Australian Standard AS1905.1:Fire Resistant Doorsets. 10 year manufacturer's warranty