S2S Red designed with a unique, different bend profile: the majority of shafts for players with better swing fundamentals follow a similar progression of stiffness of butt firm/center firm/tip stiff over their length. The butt stiff/center soft/tip stiff design of the S2S Red breaks this tradition to offer the better player a high performance shaft for better control with solid, not too stiff feel.
S2S Red shafts are for golfers with an above average to forceful transition and average to fast tempo with a later to very late release to deliver more clubhead stability at impact for control and accuracy but without a ‘boardy stiff’ feel.
Fitting difference between S2S Red and S2S Black: the S2S Red and the S2S Black shaft designs can both be played by any golfer with a later to very late release, but the S2S Red is a better fit for the golfer who is a little to a lot more forceful and aggressive on the downswing while the S2S Black is a better fit for the golfer with an average to slightly above average level of downswing aggressiveness.
S2S Red iron shafts offer the same butt stiff/center soft/tip stiff design in a heavier > 100g shaft weight for players who wish to switch from steel who are comfortable with a little heavier total weight in the irons.