I'm really not sure. The hubby figured out/took care of all of those things and did the research prior to buying everything. I know he told me at least once, but I forget. I deal with the animals, he deals with the hardware lol. I'll try to remember to ask him tonight.
I do know that it's working well for us so far. I am new to driving a trailer of any kind, and so far the hardest thing for me (other than backing up) is not to forget that it's back there, since I can't really feel it back there when I drive.