Whitecap Nylon Straight Thru-Hull Fitting w Barb Whitecap Nylon Thru-Hull Fittings are constructed of high quality nylon and 316 stainless steel. These thru-hulls include a barb. Whitecap Thru-Hulls are available in a wide range of sizes. See specifications below. Specifications Part Hose Size Flange O.D. Thread Length Barb Length Overall Length Cut-Out Max Hull Thickness S-3801 34 1-78 1-12 1 3-18 1-14 1 S-3802 1 1-78 1-916 1-1316 3-18 1-38 1-14 S-3803 1-18 2-38 1-58 1-78 3-18 1-14 1-14 S-3804