The TUSA Imprex Duo Fins are a dual material fin with an increased power transfer ratio compared to single material fins for powerful propulsion without fatigue. The blades are angled downwards for an efficient fin kick in the water. Dual Material Blade Harder material from the sides & tip of each foot pocket transfers energy from your feet all the way down to the tips of the fins, this combined with the softer material changes the shape of the fin during each part of the fin kick creating a scoop that will channel water to propel you through the water. Features Two material design for high performance 20-degree Angled Blade Design Multi-compound foot pocket increases power transfer to the fin blade Reinforced side-rails creates stability TUSA patented EZ Strap & buckle system Balanced Flexibility gives powerful propulsion without fatigue