Same RHC Mainsail design with an optional "Large Luff Window". The RHC was developed, using the AP Main designed shape, to be a superior sail in all wind conditions while improving speed. performance and adding durability and value with radial construction in the high load areas. The radial head and clew sections make the sail smoother while keeping the same easy to trim shape of the AP. The RHC also has a bit more depth in the forward mid-section to allow easier gear changing in breezier conditions.