Replace or repair broken or missing sliding door rollers with the Prime-Line D 1791 Sliding Door Wheels Assembly. This adjustable tandem patio door rollers replacement is used by Milgard as well as a variety of other manufacturers. Primarily used on vinyl patio doors. Made of stamped steel housing with concave steel ball bearing rollers in a golden finish, these patio door replacement wheels are strong, durable, and built to last. The housing of the sliding door rollers replacement is 3/4 inch wide and 1 inch tall with a 1/4-20 threaded mounting hole on the back end and an optional use #10-32 threaded hole on the top. A Phillips head screwdriver is required for installation of this roller assembly sliding door. For further dimensional information, please see the line drawing.