Keep your propeller protected from tangled lines and cables as well as underwater hazards. Macs Prop Savers Troll Prop SaverTM is designed to keep your outboard motors propeller from getting fouled by fishing lines and downrigger cables when youre trolling. It also protects propellers from underwater hazards such as stumps, rocks and kelp so you can get closer to where the fish hang out. Side benefits include increased thrust and improved steering. It comes in five sizes that fit outboard motors up to 50 hp. It is not intended for human protection or for high-speed operation. Key Features: Made from 304 stainless steel For outboard motors rated at less than 50 hp. Can be under the cavitation plate on motors equipped with a hydrofoil Increased thrust for steering and low-speed operation One-year warranty.