All Gorilla Axle's metal components (cvj housings, cages, races and bars) are made of American Made ultra strong 4340 Chromoly Steel or 300M Alloy Steel, which is machined to a precise fit for your Atv/Utv or SXS...making Gorilla Axles over two to three times stronger than OEM axles or other Chinese made replacement axles.
All components (the entire assembly) are heat treated and cryogenically treated (dual-heat) to ensure ultimate strength in vulnerable areas.
Oversized CV Joint Housings offer increased strength and durability. They allow up to 40° of articulation. DOUBLE PLUNGING AND Designed to slide on the bar splines that will provide up to 2.5" of overall travel to work on any terrain. Covered with puncture resistant heavy-duty Neoprene Boots that are durable in high and low temperatures. Then they are filled with Lucas Oil’s Xtra HD High Temp Grease to make sure the axles keep running as smoothly as when they were assembled, even in the harshest riding conditions!
 
Manufacturer's Link