Made of durable nylon plastic, improves the durability and stability of fin, having an essential role when it comes to increasing stability, balancing steering maneuvers and traction. Easy to Install: The single center fin comes with streamlined design, easy to install and decrease the water resistance, it is easy to attach and to remove without any tools, convenient to carry. Compatible Size: The size of surfboard fin is 21.3*18.4cm, works on most SUP or surfboard with a standard fin box, durable and stable ensuring your safety while surfing. Simple Design: Paddle board fin is designed detachable with slide and lock fin box system,which comes with a fin dock to connect the board and fin,easy to install and remove. Wide Application: Suitable for all kinds of inflatable surfboards, including short, long, stand-up paddle boards and so on, divide water and reduce water resistance. Features: - Our center fin has a clip for attaching or detaching to the fin dock.Slide and lock fin box system makes it removable center fin for inflatable paddle boards. - Polished surface, will not hurt your hand, makes it more stable. A smooth, hard - wearing surface is more suitable for water sports. - The water fin acts as a stabilizer assisting the rider with improved speed and steering maneuverability when paddling on the water. - High strength and durable, delivers outstanding pivoting and guiding performance, and can keep you at good balance when surfing and paddling. - Surfboard fins are made of high quality nylon plastic, with hardness and durability, can adapt to very large waves. Specifications: Color: Black Material: Nylon Size: 21.3 * 18.4 cm, chassis width 3.4 cm Package includes: 1pc* insert surfboard paddleboard carabiner Warm Tips: Please allow 2-3 mm differences due to manual measurement.