ScubaPro Twin Jet Full Foot Split Fins Durable Monprene construction will last a lifetime of active diving. Patented split fin propeller technology produces lots of propulsion with minimal effort. Drag-reducing vents where foot pocket and blade meet radically decrease drag on both up and down strokes. Foot pockets extended soleplate allows you to maximize the amount of energy you expend on each kick without wasting energy. Blades are angled to provide symmetrical power, creating a smooth and stable kicking motion that gets you moving without wearing you out.