Description This is a boat tail rudder which is made from nylon materials with good toughness, high strength, low weight, high impact resistance, high heat resistance. Increase the stability and direction of the surf bar. Professional installation is highly recommended. A nice helper for you boat. Features -Color: Black. -Material: Nylon. -Size: About 4.3 x 1.3 x 1cm/1.69x0.51x0.39 inch. - Made from nylon material for durable long time use. - Used for all kinds of inflatable surfboards. - The water splitter of the seat board is glued to the back end of the reverse side of the board. - It is glued to both sides of the plate surface to assist the use of the central water splice. - Increase the stability and direction of the surf bar.Package list: 4 x Boat Shark-fin