The Attwood Hydro Stabilizer Planing Fin Whale Tale is designed for freshwater use and is manufactured in the United States. With a unique whale tail design, this stabilizer fin helps improve the stability and maneuverability of your boat. Made by Attwood, a trusted brand in boat parts, this product is compatible with Atwood engines and offers reliable performance on the water. Perfect for enhancing the performance of your outboard engine, this planing fin is a must-have accessory for any boater looking to improve their vessel's stability and control. these come with mounting hardware. You’re getting what you see in the pictures. These are compatible up to 350 horse.