Five Oceans 1/2" NPT Thru-hull Stainless Steel FO-376 PIPE THREAD TYPE - 1/2" NPT (American National Standard Taper Pipe Thread). MADE FROM high-quality AISI316 Stainless Steel TAPERED for sealing, often without any thread sealant; for connections in nearly every type of service TOTAL LENGTH: 2 1/2" (64mm) FLANGE DIAMETER: 1 9/16" (40mm) FLANGE HOLE THICKNESS: 3/16" (5mm)