Made with the quality Kwikset is known for, all these door knobs are backed by a lifetime mechanical warranty. They come in a wide array of styles, so you'll be sure to find just what you're looking for; plus, the Kwikset Knobsets are available in half dummy, passage, privacy, and keyed entry functions so you can find a knob for almost any application. Easy to install, Kwikset Knobsets fit all pre-drilled doors and will fit 1-3/8 inch and 1-3/4 inch door thicknesses with an optional backset for 2-3/8 inches or 2-3/4 inches.