This is a 3-1/2 in. diameter door cover backplate. It is constructed from stamped steel and comes in a bright brass finish. They will cover marred spots on you doors and allows a conversion from 2-3/8 in. to 2-3/4 in. backset, or 2-3/4 in. to 2-3/8 in. Your doorknob will be the only item used to secure this to your entry door. No other fasteners are required to install your new door cover backplate.