The J-Style Folding Kayak Rack is designed to transport your kayak or canoe on its side to save space, allowing a second kayak or canoe to be mounted on the other side of the roof rack, depending on the length of the crossbars. When used in conjunction with an S512X extension piece, it is possible to transport up to 4 kayaks or canoes on your roof rack, depending on the length of your crossbars.