Stanley National N100-875 Stay Roller Zinc Designed For Use As A Guide On Large, Sliding Doors Up To 2-1/4" Thick By Side Mounting To Building Embossed Frame With Two Wings Provides Greater Bracing And Holding Strength Versus Conventional Single-Support, Corner-Iron Frame Delrin Wheel Ensures Rust-Free Operation And Is Formed To Prevent Dirt From Clogging Or Accumulating Convex roller wheel prevents gouging of door, Roller is adjustable