I do not know much about trailer and big vehicles but I know of someone who does. She is a lady and she knows a lot about big machinery and big trailer vehicles industry. I admire her a lot because there is not many ladies who are interested in knowing all these details that includes trailer hitches and all the bolts and nuts stuff. Furthermore, she make this as her career, getting involved with the marketing and sales. As I said, I admire her, she is a gutsy lady!