One standard 6 hole aluminum trailer hub cap and mounting gasket. Hub cap kit Includes oil window, vent plug, and side pipe fill plug, 6 mounting bolts. Die-cast from aluminum alloy to help dissipate heat, resist breaking, warping and cracking. Bolt holes = 6, bolt circle = 5 1/2”, bolt hole size = 5/16”, fit = Trailer. Replaces: Stemco️#343-4009 SKF️#1643. Approximate dimensions = flange OD 6 1/4″ flange ID 4 3/8″ height 2 11/16″. Approximate net weight = 15.4 oz.