These vintage style door knob rosettes are constructed of stamped steel and come in a satin nickel finish. This type of rosette is designed for indoor use only, and it is used with other vintage style hardware by Prime-Line Products and other classic hardware manufacturers. These rosettes feature an inside diameter of 1/16 inch, and outside diameter of 2-1/2 inch and have a 2 inch mounting hole center spacing. Note: If attempting to use these rosettes on doors with large, pre-drilled knob holes, the fasteners of these rosettes require a solid surface to mount to. The large 2-1/8 inch (approximate size) pre-bored holes must first be filled with a hardening filler, to then be able to receive the rosette fasteners. Installation tip 1: Products like Fix-It-All® and Bondo Body Filler® have worked well for some, but care must be used to avoid damaging any prefinished door surfaces during application and finishing. Installation tip 2: Apply a small amount of Loctite ThreadLocker 271® to the set screw threads in the event they are loosening – Loctite® purchased separately. From the Manufacturer These door knob rosettes are constructed from steel and come plated in satin nickel. They feature a screw mount design with a 2-1/2 in. diameter. These style rosettes fit on old style passage locks.