The Prop Shaft Anode for the Lowrance Ghost® trolling motor allows for use in brackish water without voiding the Lowrance Ghost trolling motor warranty. The Prop Shaft Anode is a ring-shaped fitting that is installed over the existing propeller nut, on the back of the propeller. The anode prevents corrosion that could result from using the trolling motor in brackish water. NOTE: Using the Ghost Trolling Motor in saltwater WILL void the warranty.