The part is HD300 Outboard Hydrofoil Stabilizer, Sterndrive Whale Tail Suits most outboards and inboard/outboard sterndrives 40HP to up 350HP. Dimension: 14.4'' x17'' Include SS bolts/locking nuts/SS washes/rubber washes. Features: Improves steering at both low high speeds. Reduces or eliminates porpoising and cavitation. Fast planing and lower onplane RPMs save fuel and increase safety. Crescentshaped surface funnels water flow for more thrust and control. Especially good for deck boats,pontoon boats and bass boats. A'must have' for skiers, wakeboarders, etc Helps lift the skier out of the water much quicker 3 models of hydrofoil stabilizers on choice: HD200 for engine 8HP to 40HP. HD300 for engine 40HP to 350HP. HD150(dual fins) for engine up to 150HP.