The Hillman Group The Hillman Group 4329 3/4 ID x 2-1/4 OD x 1/8 In. Large Neoprene Washer (6-Pack) Neoprene washers hold up to oils, food grade acids, grease and solvents Washers provide a greater bearing surface under the fastener. This helps prevent a nut, bolt or screw from pulling through the material Made of black neoprene to prevent corrosion Providing a reliable seal and dependable strength where these liquids are used