Ideal for fast trolling, heavy baits or handling big fish.316 Stainless Steel.Nylon washers provide smooth rotation.Fits inside a rod holder butt with 40mm or larger inside diameter.Use with either 30° or 90° rod holders.Swivel friction and tension is adjustable with a Stainless nylock nut.Will raise your rod holder pin depth 38mm after inserted.Other Details: Part No. Description O.D.(mm) Height(mm) 49660 Stainless Steel Rod Holder Swivel Insert Adapter 38 57