Product Description These vintage style door knobs are constructed of steel and come finished in a bright brass plating. This set of knobs is designed for indoor use only, and it includes a 17/64 in. x 3-1/2 in. steel spindle with 3/8 in. -20 threads. This classic style knob set fits square drive spindle systems commonly found in antique and vintage door hardware sets, and it can adjust to accommodate different door thicknesses. The shanks on these knobs include set screws for fastening the knobs to the square spindle, but it does NOT include any of the following components and they must be purchased separately: The internal mortise lock body, the door rosettes, the trim and strike plates, or the latch and fasteners. For SOLID BRASS knobs, kindly see Prime-Lineft.s model number E 2297. Note: This item cannot be used on pre-bored doors that have large, newer style door knob holes without first prepping them to receive this hardware. *Installation tip #1: Because the fasteners of the rosettes (purchased separately) require a solid surface to mount to, the large 2-1/8 in. (approximate size) holes must first be filled with a hardening filler, to then be able to receive the rosette fasteners. 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 knobs are constructed from steel and come finished in brass. The knobs have a projection of 1-3/4 in. and a 9/32 in. square spindle. Easily fits on doors that are 1-3/8 in. thick.