Prime-Line D 1584 Sliding Door Roller Assembly with 1-1/4 inch Steel Ball Bearing Product Description This patio door roller is constructed from steel. It comes affixed to an adjustable steel housing assembly. Used by Northrop and other glass door manufacturers. From the Manufacturer This patio door roller is constructed from steel. It comes affixed to an adjustable steel housing assembly. Used by Northrop and other glass door manufacturers. Features Used by Northrup and a variety of sliding patio door manufacturers When the corner screw passes through the F-tab the assembly is captured by the side stile and bottom rail as the screw draws the two sides together 1-1/4 in. diameter concave ball bearing roller Stamped steel housing and steel rollers Used on metal framed sliding patio doors Easy to install USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.