These passage door latches are constructed of steel and come in a chrome plated finish. This latch is designed for indoor use only, and it functions with the use of a spring-loaded square drive spindle at a maximum width and height of 9/32 inches. It is used with antique and vintage door hardware and it features a 2-3/8 in. backset. The latch includes a latch strike and fasteners, but it does NOT include any of the following components and they must be purchased separately: The door knobs, square spindle and rosettes. *Note #1: The square drive on this latch has a 9/32 in. opening and a 5/16 in. opening, but it will NOT accommodate 5/16 in. square spindles. The maximum square spindle size that this latch will accommodate is 9/32 inches. Note #2: 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.