Perko 3/4" Thru-Hull Fitting w/ Pipe Thread Bronze. Flange is machined to fit hull and grooved to retain bedding compound. Neck. is threaded to approximately 3/8 inch from flange.. Cast bronze.. Technical Information:. Pipe Size Inches: 3/4. Mouting Hole Diameter Inches: 1. Maximum Hull Thickness Inches: 1-1/2. O.D. Flange Inches: 1-7/8. Model Number: 0322DP5PLB. Ship Weight: 2.4/11.6 lbs.. MADE IN THE USA