Happy Troller - Large Plate Large Troller: Fits inboard/outboards plus all outboard motors 50 hp and larger.For the Fisherman who thinks he has everything!Slows even big motors down to that "ever-so-slow" fish tantalizing speed.A significant invention in the sport of troll fishing, Happy TrollerA(R) mounts on the anti-cavitation plate to allow fine control of trolling speed. At cruising speed, your boat&';s stability is enhanced.Locks in "down" position for trolling.Locks in "up" position for cruising.Happy Troller is the answer to correct trolling speed. Use it year-round in all boating activities; salt and fresh water.Key Features: Reduces troll speed in "down" position Acts as a stabilizer in "up" position Maintains stability in bow-light boats Smooths out ride in rough water Reduces porpoising and cavitation Made of only highest quality stainless steel and marine aluminum; clear anodized aluminum finish Installs in 15 minutes Stainless steel mounting hardware and installation & operating instructions provided with each unit Owner&';s Manual (pdf)