Perko 1/2" 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: 1/2. Mouting Hole Diameter Inches: 13/16. Maximum Hull Thickness Inches: 1-3/8. O.D. Flange Inches: 1-1/2. Model Number: 0322DP4PLB. Ship Weight: 1.8/7.9 lbs.. MADE IN THE USA