The perfect combination of comfort and power for recreational divers and snorkelers. The mid-sized blade has three channels for optimal movement of water during the kicking cycle. Ideal for travel and available in XS providing the perfect fin for both women and young divers too. Mares Plana Avanti X3 Open Heel Dive Fins Channel Thrust Technology When water spills over the sides of the blade, it reduces thrust, and decreases efficiency. Mares design was derived from observing marine mammals such as manatees in their natural environment. When swimming they bend their tail to form a channel, which optimizes thrust. When proper channeling occurs, all of the displaced water contributes to thrust. The "Channel Thrust" technology maximizes the channeling of water and moves a much greater amount of water compared to other fins of the same size. The result is greater thrusting power with the same amount of effort. Mares latest development in "Channel Thrust" technology is the new "Superchannel" design. "Superchannel" further increases the high performance level of Mares fins.