Arcs are ram air foils. Firstly foils are either closed or open cell. Secondly their bridle is static, depower or none. EG... Open cell, with depower bridle : Frenzy, Flexifoil Sabre, Naish Element etc Open cell, with static bridle: Blade, Advance Offroad, buggy kites, etc. Closed cell, no bridle: P...