C.E. Smith 4 foot roller bunks are trailer bunk assemblies for loading and unloading small craft, including situations where floating the boat onto the trailer is not practical. They come pre-assembled and pre-drilled, and may be installed with mounting brackets, bolted to a trailer frame for a flat bottom boat, or mounted on existing bunk boards. Brand: C.E. Smith Product type: roller bunks Length: 4 foot Rollers: 2 inch polypropylene rollers Shafts: 1/2 inch shafts Channel: heavy gauge pre-galvanized channel Capacity: supports up to 1500 lbs of well distributed weight Installation: pre-assembled and pre-drilled Mounting hardware: not included Quantity: sold in pairs Warning: this product can expose you to chemicals including arsenic, cadmium, beryllium, cobalt metal powder, nickel metallic, chromium hexavalent compounds, and lead, as listed in the current product warning.