This is one of the DIY ring and back plate kits. I think the ring the plate are 5/16" the bottom and top pieces are 3/8" and then later on I'm going to put 1/4" on the side. I welded to here and layed this solid bead on top before my 85amp welder kicked out /forums/images/graemlins/tongue.gif Added in some skids from 3/8" and 1/4" leftovers, also act as gussets. Should help to slide over stuff without slamming the diffcover on things. And yes I'm going to round them off and make them flush.