The nanazero's FLEX center fin is designed to complement the nanazero MID01, with its narrow base (width of the root) and fin area providing excellent acceleration and speed during turns. It's also a great match for shorter 6-7 feet mid-length surfboards, even those not from the nanazero brand, enhancing speed and turning capabilities. *Please ensure compatibility with the fin box specifications. *The order includes only the center fin; side fins are not included.