These anodes are made with an aluminum alloy which is specially formulated for marine anode use. They last longer than zinc anodes and, utilizing a less toxic activator, are safer for the environment. Streamline Collars are the anode of choice for propeller shaft protection as the football shape minimizes turbulence and drag. These anodes feature precise internal sizing for maximal contact with the shaft for best protection. All Sea Shield aluminum anodes conform to Mil Spec MIL-A-24779 for maximum protection. Affords protection in brackish as well as salt water More economical than zinc anodes Less than half the weight of comparable zinc anodes Designed by divers, for divers Captive stainless steel Allen Head fasteners for easiest underwater installation - no slot for the driver to slip out of Threads are tapped into the anode for super easy installation - no cross-threading, no galling Lock washers prevent loosening under vibration Made in California, USA
