Groco Stainless Steel & Bronze Thru-Hull Fittings have straight NPS barbed male pipe designed to be used with a hose. Their stainless steel construction offers the ultimate in corrosion resistance and protection. It is recommended that Groco SS thru-hull fittings only be used in low pressure applications. SS thru-hull are the best choice for below the waterling use. They are supplied complete with a stainless steel locknut with bonding screw. Or Bronze.