Heavy galvanized coating. I actually cut this up into 4 rectangles because I needed “captive” washers with square holes for a trailer hitch. Worked perfectly and was considerably cheaper that getting them from trailer hitch supplierI installed this one on my boat house dock just ahead of my pontoon. It provides excellent assistance for on and off traffic. I used 1 1/2” marine galvanized 1/2” lag bolts. It’s very sturdy!I was having trouble with frost heaves lifting my deck stairs and generally making a mess of the deck itself. So, I refitted the stairs with these hinges, so now the stairs can move up or down with the ground level ... just as a boat dock does with the tides.V hull boats can be difficult to get into from a tall dock. These rails were just the ticket for making an easy boarding and exit without worrying about falling into the lake.Nice hinges. Sturdy. Work well on our dock.Very handy on the floating dock where we get on and off the boats. Seems strong enough to take all the abuse we can hand out.I'd get 3 more if they cost less.These work perfect. Made my dock assembly easy. Buy with confidence.Description is not correct - this is for ONLY the hinge pins - NOT the complete hinge assembly.Have seen other reviews with the same issue - Amazon needs to correct the listing