This is the Tusa Imprex Duo Open Heel Fins for Scuba Diving and Snorkeling 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 and buckle system Balanced Flexibility gives powerful propulsion without fatigue Colors: Black (BK), Fishtail Blue (FB), Flash Yellow (FY) The SF0102 Imprex Duo fin features TUSA&';s patented Angled Blade Design and multi-compound foot pocket, increasing power transfer to the fin blade. The Imprex Duo also features a two material design for high performance and reinforced side-rails creating stability, for powerful propulsion without fatigue.