I work at Utility Trailer Mfg. The above info is correct. Here is some helpful info too. Standard airline size is 3/8 od, some companies order 1/2 inch airlines. 5/8 airlines are either black or a lime green color. ABS harness are orange from where they drop out of the raceway to the rear sub assembly.( rear axles). Brake cans or actuators are black with silver or gold 1/2 caps. Ours are never painted, DOT regulations on that part. On our trailers the electric and airlines run down the center on reefers and down the roadside on dry vans. Roadside = drivers side or left side Curbside = passenger side or right side It was confusing at first but after a while it is not left or right it is road and curb. I catch myself doing alot especially when people look at you like what the heck did you say. My wife is used to it now after 19 years with Utility.