Receiver adapter is made by Buyers. It's a PM84. One height, same line height as the receiver. Made for 2" receiver. The H3 has a 2" receiver. Most trucks do.
Pintle hook is 15ton capable. Buyers PH15. There are of course other sizes available. 5 ton, 8 ton, 20 ton. Depends what you want.

I think the whole thing was like 80 or 90 bucks. I can't remember and wasn't really monitoring the price all that much; I was going to make it regardless.

Chain plate is USGI, bought on ebay. Hard to find! around $20 or $25.