4" x 36" Sanitary, 304 Stainless Steel, Tri Clamp SpoolTri Clamp Spool 4" Bore by 36" Long with Tri Clamp Fittings Stainless Steel 304 Tri Clamp Spool Spools, also known as sanitary tri clamp spools, are pre fabricated lengths of stainless tubing with Tri Clamp fittings welded to both ends for customer convenience. These can be used in conjunction with other Tri Clamp fittings, Tri Clamp Clamps and Gaskets, allowing the user to easily manufacture sanitary pipelines without the need for costly on site