Forward Controls Design's AA (All Angles) designation refers to a control surface's ability to offer equal traction from all angles of approach. Unlike horizontal or vertical serrations, where optimum traction is achieved from approaches at a perpendicular angle, and decreases as angles move near parallel to the serrations, a dimpled or cross hatched surface is indifferent to angles of approach, and provides the same amount of friction/traction to all comers.
The use of dimples on control surfaces isn't new, we believe we've done it better than anyone. We use several dimple sizes and depths to maximize the numbers of dimples on the surface. The pattern has improved from several trials and errors. Current dimple sizes, pattern, and depth are based on the third redesign, the effectiveness of the AA control surface has not only equaled (our minimum requirement), but surpassed that of a serrated surface.
Forward Control Design's AA option can be found on LDFA, ABC/R v2, and EMR-A.
This SLR receiver has both an ABC/R-AA v2, and an EMR-A, AA. Photo courtesy of David S.