Product-related text: - Suitable for door thickness: 35mm-55mm, suitable for wood, fiberglass or metal doors. - Easy to install, replace your door viewer in 5 minutes with no tools required. - The lens will secure your home against burglary, intrusions and home invasion. - 220 degree viewing angle provides the security of identifying visitors from behind a locked door, You can easily view the entire surrounding area from the top of the head to the feet of someone standing outside. - A heavy duty viewer cover increases your security. With the cover in place, visitors outside cannot see through the viewer into your home, offering the highest level of protection and safety!