The 220-degree viewing angle provides the security of identifying visitors behind a closed door; you can easily see who is standing outside. The lens consists of a convex lens, focusing tube, concave lens, washer, convex lens, and metal frame, ensuring durability and a long lifespan. Applicable door thickness: 35-60 mm / 1.4-2.4 inches, suitable for doors made of PVC, fiberglass, or metal, effectively protecting your home from theft and intrusion. Easy to install, the door viewer can be replaced in 5 minutes without tools, providing the highest level of protection for your security and convenient use. A sturdy viewer cover enhances your security; after the cover is in place, visitors from outside cannot see through the viewer into your home, protecting your safety.