The TeraFlex HD44/CRD50 differential covers are designed to offer extreme protection from rocks, obstacles and other debris on the trail. The cover is cast from the same high-strength ductile-iron as our HD axle housings. The cover is over 3/8″ thick to ensure protection. It also offers two fill plugs for use in standard or high pinion D44 housings, or when the pinion must be rotated in extreme applications. Fits all Dana 44 housings- standard & high pinion, TeraCRD50R housings.