saruSURF US box center stubby fin hard 4.6" for River SUP/longboard/airSUP Black Hard plastic 4.6" fin for any US box surfboard or inflatable SUP with AIR7 fin box (or foam surfboard with AIR7 fin box or US box compatible) , (base is 7.3 inches long, if your fin box is not long enough, this fin will NOT fit, PLEASE measure your fin box and or ASK us before you buy) STAINLESS STEEL FIN SCREW saruSURF brand US box center fin, fin screw included, no need to screw drivers, adjust your in position (forward, backward, take it off) anytime even out on the water! (base is 7.3 inches long, if your fin box is not long enough, this fin will NOT fit, PLEASE measure your fin box and or ASK us before you buy) for longboard / (stand up paddle) SUP / airSUP / river SUP (base is 7.3 inches long, if your fin box is not long enough, this fin will NOT fit, PLEASE measure your fin box and or ASK us before you buy) great for center subby when SUP surfing / longboard surfing! (base is 7.3 inches long, if your fin box is not long enough, this fin will NOT fit, PLEASE measure your fin box and or ASK us before you buy) great for surfer : shallow reef / dumping shore break / white water SUP (base is 7.3 inches long, if your fin box is not long enough, this fin will NOT fit, PLEASE measure your fin box and or ASK us before you buy)