Valley Irrigation genuine parts. Machined worm drive Image may not be subject to product specifications. Made from high strength ductile iron provides significantly longer wear life than steel and prevents gear tooth wear. Industry-exclusive 25° tooth angle provides 40 percent more strength, longer life and better reliability in tough conditions compared to normal 14.5° tooth designs. 52:1 Gear ratio as part of fully recessed tooth design keeps oil between engaged gears.