The detachable large fin, the SUP board is designed with 3 fins, and the middle fin needs to be installed (the direction is the same as the other two fins). The inflatable stand-up paddle board can be inflated to 12PSI in 10 minutes by pulling the air pump. Easy Carrying Backpack satisfies a Paddling Travel! The SUP board and all these accessories can be disassembled and put into the backpack, making it easier to go to the beach and lakes. We ONLY accept the return for original package.Please make sure that item has NO man-made sabotage. Used items will not be accepted for return. You bought wrong model or wrong color. We promise to help you solve it asap, and make you feel satisfactory absolutely. This item is in the category "Sporting Goods\Water Sports\Stand Up Paddleboarding\Stand Up Paddleboards". The seller is "hotboomu" and is located in this country: US. This item can be shipped to United States.