Schmitt & Ongaro - Deluxe Adjustable Arm w/Adjustable Tip 12" - 18" Ultra HD - 33660. Standard wiper arm, adjustable J-Hook and adjustable tip, black powder coated stainless steel, heavy duty stainless steel spring, easy installation, replaces most competitive arms, 5/8" shaft, available in sizes 12"-18" & 19"-24".. Features:. 5/8" Shaft. Powder Coated 304 Stainless Steel. HD Stainless Steel Spring. Will replace all Competitive Arms on HD motors