Genuine black porcelain knob measures 2 3/8 inches in diameter (approximate) and has a projection of 2 1/4 inches. Solid brass rosette plates screws directly into the door with four wood screws and measures 3 inches in diameter. The dummy door knob is a fixed knob with double rosettes and is commonly used on French-style or bi-fold doors. The double sided dummy option can be used with or without a borehole, if no borehole is present countersinking may be required. This knob set with fit any door thickness between a standard 1 3/8 inch to a 2 1/4 inch thick. This door knob set is available in several finishes and functions. Passage (Hall/Closet) and Privacy (Bed/Bath) sets come complete with the functioning hardware and a 2 3/8 inch back-set is standard. A 2 3/4 inch back-set is also available upon request. This particular product has a lead time of approximately 3 to 5 business days.