Why hire a locksmith or struggle with a chisel when you can install doorknobs yourself with minimal effort? The Porter-Cable 59375 is a professional quality kit that makes it a snap to mortise latch and strike plate openings with any collet router measuring 1/4 inch. The various settings for strike and latch plate sizes ensure precise results. (The strike plate sizes include 1-1/8-by-2-3/4 inches, 1-1/2-by-2-1/4 inches, and 1-1/2-by-2-3/4 inches and latch plate sizes of 1-by-2-1/4 inches, 1-1/8-by-2-1/4 inches, and 1-1/8-by-2-3/4 inches.) Compatible with doors with a thickness of 1-3/8 inches and 1-3/4 inches, the 59375 comes with a high-speed steel router bit and bearings, brads, and instruction manual.