This Vertical Flush-Mount Fishing Rod Holder features a hard black polymer liner and flange gasket with integral flip-up cap to keep water out when not in use.Flange: Chrome-plated bronzeTube: Stainless steelLength Under Flange: 9"Tube Inside Diameter: 1 5/8"Tube Outside Diameter: 2"Flange Outside Diameter: 3 1/2"