I was surprised how sturdy the Stainless is, and the contents they ship with it. These are a steal compared to other galvanized or stainless steel type fastener. I’ve bought 6, and all of them fit snug on pressure treated 6” x 6” milled lumber, 5.5” x 5.5” ) like you get at your lumber yard or big store. They should not have used the word “rough” lumber when describing the fit, because you will need to shave a half inch or more. Even the milled standard 6” x 6” is sometimes 6 5/8” or greater, and I’ve just taken a grinder with a 40 -60 grit abrasive pad and trimmed it down a bit. Well worth the little effort of labor you need to put in. I used longer 3/8” stainless wedge anchors, because I had them on hand, otherwise they include all the hardware you need. Again, it depends on your application and any codes that are required. I will usually err on the side of caution, and go for thicker and longer hardware ( that’s what she said” ) when possible