Used to allow a user to identify visitors from the security of a locked door. Glass lens. Offers 160 degrees lens angle for wide viewing. Zinc die cast body with an oil rubbed bronze finish. Requires a 1/2 inch hole and can be used in doors that measure 1-3/8 to 2 inch thick. Exterior width is 5/8 inch. Interior width is 9/16 inch. In Poly Bag.