High quality material, durable and never fade. Safer with the cover, visitors outside cannot see through the viewer into your home. 220 degree viewing angle provides the security of identifying visitors from behind a locked door. Adjustable length, easy and convenient to install. Suitable for 35mm-60mm thickness door, wooden doors, security doors, fire doors, ect. Specification: Material: Zinc Alloy Viewing Angle: 220 Degree Shortest Length: Approx. 42mm / 1.65inch Application: 35-60mm / 1.38-2.36inch thick Size Chart: 1# 2# 3# 4# 5# 6# Peephole Diameter: Approx. 25mm / 0.98inch Pipe Diameter: Approx. 14mm / 0.55inch Cover Diameter: Approx. 22mm / 0.87inch 7# 8# Peephole Diameter: Approx. 30mm / 1.18inch Pipe Diameter: Approx. 16mm / 0.63inch Cover Diameter: Approx. 25mm / 0.98inch Package Includes: 1 Piece Door Viewer Note: Since the size above is measured by hand, the size of the actual item could be slightly different from the size above. Due to the lighting effects, monitor settings, etc. There could be some slight difference in the color of the pictures and the actual item.