Groco Hi-Speed Strainer with Nut The Groco Hi-Speed Strainer is a NPT combo scoop thru hull that is designed for increased flow compared to standard thru hulls. This strainer is constructed of C83600 bronze and is available in a variety of sizes. Scoop thru-hull NPSM NPT combination thread C83600 bronze construction Includes nut Part Number Thread NPS A B C D Weight STH-750-W 34 2.20 1.05 4.00 3.05 0.95 lbs. STH-1000-W 1 2.85 1.05 4.00 3.05 1.25 lbs. STH-1250-W 1-14 2.90 1.20 4.30 3.35 1.75 lbs