The Positive Drive Fins (PDF’s) use a unique ellipsoidal blade to generate the correct propulsion in all swim strokes. Traditionally fins are not made for Breaststroke, but the asymmetrical shape and adjustable heel strap allows the swimmer to safely build power in the Breaststroke kick. The short and wide blade design also promotes a natural inward supination kick style for Backstroke, Butterfly, and Freestyle. The fins use an ergonomic foot pocket to comfortably set your feet into the ideal swimming position. The heel strap helps secure the fin and allows the foot to flex more naturally. A closed toe design provides better energy transfer from leg to foot. The PDF's will help you train your technique in all four strokes making them great for individual medley training Features Ergonomic Foot Pocket - Comfortable place the foot into an ideal swimming position. Ellipsoidal Blade - Generates correct propulsion in all kick styles. Asymmetrical - Promotes a natural inward supination kick cycle. Adjustable Heel Straps - Creates a customized fit that secures the fin and allows for the feet to flex naturally. Closed Toe Design - Provides superior energy transfer. All Four Swim Strokes - Increases leg strength, foot speed and ankle flexibility in all for competiton strokes. Breaststroke Compatible - Safely build a powerful breaststroke kick. Comparison Chart