Boat Thru Hull Fitting made of 316 Stainless Steel for durable use and long time services Carefully Polished to a beautiful, mirror-like finish Maximum corrosion resistance and durability in the saltwater environment. Thru-Hull Connections: excellent corrosion resistance to UV & weather-aging Straight Thru Hull Fittings are for use with hose; Mounting Hole Diameter: 1 inch (25mm) / 1-1/4 inch (32mm) Specification: Color: Silver Material: 316 Stainless Steel Size 1: Overall Length: 3 inch (75mm) Mounting Hole Diameter: 1 inch (25mm) Size 2: Overall Length: 3-1/2 inch (85mm) Mounting Hole Diameter: 1-1/4 inch (32mm) Package Includes: 8 Pieces Boat Thru Hull Fittings 4 Pieces Nuts Note: Please allow 1~3mm differs due to manual measurement. (1 inch = 25.4mm) Product color may vary slightly from what appears online due to monitor differences.