These bar pile holders are made of 1 " round steel on a 2 " x 3/8 " plate. Slip it over your existing piling and bolt to your dock or bolt to your dock, then install the piling (recommended). Sizing note: Always use the next size larger hoop. For example: if you have a 8 " ID piling, use a 10 " hoop. All steel components are hot dipped galvanized.