Made of all 3/8 inch material. This bracket bolts to the 10 cover bolts to allow the use of a GM 8.5 10 bolt to be put into a Cadillac for stock shows where welding to the housing is prohibited. It does sot close enough to the axle tubes where the bracket can be welded to the axle tubes if rules allow. This kit comes with the 10 back cover bolts and two 9/16 inch bolts, washers and nuts. Test fit bracket on housing before installation, certain castings may need to be slightly clearance with a grinder.