These are the same Fat Sacs we had custom designed to fit in 2006 thru 2008 MasterCraft X-2 and X-15 wakeboard boats. Each bag adds aver 400 lbs. of ballast to help shape up your wake for monster air. We recommend purchasing the kit if you want to tie these into your factory ballast system where you can use the factory pumps. These sacs are custom fit so they won't bunch or bind in the rear storage compartments. Take your wakeboarding and wakesurfing and to the next level with the ultimate ballast bags for your 2006 to 2008 MasterCraft X-2 or X-15. Tey also work great in MasterCraft X-30's and X-45's! These bags feature the worlds strongest ballast bag construction and are extremely resistant to rips, tears and abrasion. Installing this kit yourself? Check out our detailed Installation instructions at www.waterskis.com/x2ballastinstructions Note: This bag does not fit 2009 X2 and X15 and does not come with fittings.