The latest Iron Instinct watercolor shafts are unique in that they come in three distinct specs for long(4567), middle(6789), and short(PGS) irons.
Each shaft is specifically designed to bring out the best performance of each club. In longer irons, the slightly lighter, more flexible shaft is more forgiving and gets the ball up in the air quicker; while the mid- and scoring iron shafts are firmer for more control and feel, yet allow pinpoint accuracy in a lighter package.
All three types of shafts are total 39" with a tapered 0.355" tip and can be inserted into the club without tipping. The shaft can be trimmed from the butt end. For a firmer feel, increments of 1/4" up to 1" can be tipped.
One notable advantage of the shaft is that a golfer can choose to fit a set of irons with the same spec shafts, or to pick and choose shafts for irons that are more difficult to hit, like the 4 or 6 iron.