The FINIS Positive Drive Fin (PDF) is truly an innovative product. Not only does this fin add speed to dolphin and flutter motions, it also allows the swimmer to generate power safely through the Breaststroke kick. The ability to use these fins through the duration of an IM workout sets them apart from the rest. No longer do you have to substitute dolphin kick on the Breaststroke lengths. Instead, you can practice generating power through every kick, as it is meant to be used in the race. The amazing versatility and fit of this fin are like nothing else on the market today.