This extra heavy-duty 1-1/2 inch diecast zinc tandem roller assembly is designed for Kawneer sliding patio doors and other heavy-duty sliding door applications. Featuring two concave (grooved) inline stainless steel ball bearing rollers in a diecast outer housing, it provides smooth, quiet operation and long-lasting durability. Rear adjustment allows precise alignment, while the housing includes two 1/4-20 mounting holes on the back and two on top for secure installation. Built to withstand severe weather conditions, this assembly is perfect for DIY homeowners or contractors seeking reliable performance. A Phillips head screwdriver is required for installation.