These bar pile holders are made on 1 " round on two 1-1/2 " x 5 " x 1/4 " plates. 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.