Ring and the Cover are 3/8" thick Plate steel cover bent 8 ways Machined absolutely flat for a perfect fit All seams fully welded inside and out This is our basic differential cover, we see it as the only one worth making. The Dana 60 axles are found stock on an endless variety of trucks from International Travelalls, Chevys, Fords, & Dodge trucks. The D60s end up in every kind of rig from Samurais to Land Cruisers to Jeeps and full sized trucks & buggys. The differential cover is a 1 piece 3/8" (.375") plate steel cap bent 8 ways then welded to a 3/8" ring! The fill plug is a generous 1" ID for easy fill and oil level check. The D60 is our best selling cover. After welding the mounting surface is machined absolutely flat for a perfect fit! This works on high and low pinion D60 axles along with D70 axles (same bolt pattern). Ford Super Duty D60s need to use our Super Duty Diff Cover