Heavy duty differential cover for GM 10 bolt Rear with 8.5" ring gear. OX Heavy Duty Differential Covers are made from tough nodular iron and are weldable for customization, these covers provide the ultimate in strength and guard your differential from severe impacts, such as rocks and off-road debris. They also enhance the rugged look of your axles. Each cover has "OX" badging, with fill and drain plugs and feature a lip free design for rock crawling and obstacle avoidance where necessary a must upgrade for differential protection.