Streamline Collars SL-2500 2-1/2" Shaft Zinc Weight 5.187lbs,Shaft Zinc Weight 5.187lbs Streamline Collars SL-2500 2-1/2", All Sea Shield zinc anodes conform to Mil Spec MIL-A-18001 for maximum protection,Streamline Collars are the anode of choice for propeller shaft protection as the football shape minimizes turbulence and drag, Shaft Anodes Stream Line Collars 2-1/2"( SL-2500 ) Zinc, Online Sale, price comparison shop for things you love The Luxury Lifestyle Portal Fast worldwide shipping Fast Shipping and Free Returns on All Purchases. SL-2500 2-1/2" Shaft Zinc Weight 5.187lbs Streamline Collars.