This 1 inch F-tab tandem roller assembly is designed for Guaranteed Products and a variety of other sliding patio doors. It features two concave steel ball bearing rollers in an adjustable stamped steel housing for smooth, quiet operation. The F-tab mounting allows the corner screw to pass through, capturing the assembly between the side stile and bottom rail as the screw draws the components together for a secure fit. The housing measures 11/16 inch wide with a 13/16 inch flare, 1 inch tall, and 3-1/8 inches long. Rear adjustment allows precise alignment, making this assembly ideal for DIY homeowners and contractors.