All our boat rollers and blocks are made from long-lasting, non-marking polyurethane (unless otherwise stated). This means they don’t create the unsightly black marks on a boat’s hull that some rubber products can leave. All of our boat roller brackets are made from clear zinc plated heavy duty 50x6mm steel strip and solid bar spindles, all designed for most rugged applications. These brackets may be fitted to the trailer with M10 fixings through the slots provided, hole centres 66-81mm.