The Chrysler 8.25 differential cover is fabricated from pickled and oiled metal. The front cover pieces are 1/4″ thick and the ring is 3/8″ thick. The fill hole has been drilled and tapped for 1/2″ NPT, so you can reuse your stock fill plug. It does come with mounting hardware and washers. It does not come with a fill plug. The drain hole (optional), will be drilled and tapped for 1/8″-27 NPT. If you choose to “Weld It Yourself”, I highly recommend welding the back of the cover first, welding a little at a time and letting it cool so that you don’t warp the cover.