Bought this to add a set of guides on front of trailer to guide bow into winch when i'm launching solo. guideposts alone are worth what i paid. the ubolts seem to be stainless but are around 3/8 or metric or so-a little too light for me. The square clamps seem to be galvanized steel and are fairly thin. I didn't use the ubolts or clamp pieces-although i may find use for them on a smaller boat trailer. I upgraded to heavy galvanized clamps and 1/2 galvanized ubolts from my local marine supply. these guides are around 70.00 each there so 90 for 2 is worth it and i can toss the other parts but i'll look for uses for them.