That came with my cart when I bought it. I cut a hole in a plate that I put over the ball holder. It didn't come with the bracket so I just cut the hole snug. Any automotive or marine store will have a bracket, or you could visit one to see how easy it would be to fabricate one. Simply a "U" shaped metal piece with two holes, like this:
https://www.amazon.com/Universal-Vol...41781114&psc=1
I used 16 AWG and a fuse.