UNC Hexagon full nut 3/8 inch -16 A4 Stainless Steel A4 grade stainless steel has a greater corrosion resistance than A2 in certain environments. It is often used for Marine applications especially when coming into direct contact with salt water Dimensions: 3/8" x 16 TPI 15 mm Across the flats 14 mm Point to Point 8 mm thickness