us first class postage rates by weightclass 3 receiver hitch ratingclass 3 hitch ratingclass 3 trailer hitch ratingtrailer hitch ratingfirst class stamp weightclass 3 tow hitch ratingclass 3 trailer hitch weight ratingclass 4 hitch weight ratingreese class 3 hitch ratingclass iii hitch ratingfirst class mail rates by weight
