ADVANCED MATERIALSThe Long board Center Fin Box is ribbed for better hold in the board.Made of plastic and polyethylene, which is sturdy and wear-resistant,it won't add much too weight on surf board. WATERPROOF FUNCTIONCan withstand water pressure and resistance to UV damage, durable for long time to use. EASY TO INSTALLThe slot is cut delicately, work well with all single fins, fit your fins perfectly and smoothly. Lightweight and portable,Simple to attach and to remove. MULTIFUNCTIONALTypically used in Longboards, Single Fin surfboards, surfboards, funboards, sailboards or paddle boards and as a Stand Up Paddle board fin box. PERFECT GIFTNice accessory for surfing lovers. Great for those that are backyard shapers or pro shaper. Specification: Color: 1: black, 2: white Size: 1: 26cm long, 2: 20cm long Package includes: 1pc*tail rudder box