A.P.E. Anderson/Putnam/Engineering....... Edge boards , A George Greenough design that can be adapted to most surfboards. Like having 2 boards in 1 . A narrower short board concave that runs from nose to tail with hard edges is shaped underneath a displacement Hull with full lifted rails. Works well in all conditions even wind and chop , but really excels when the power comes on . Pure Greenough logic , thanks to George !