The most flexible shaft available are commonly referred to as ladies flex and are designated by the letter "L". While used most often by women, some older men may want this designation as well, and women with higher swing speeds tend to avoid this flex. The added flexibility allows for aging golfers to regain some of their lost distance. If your typical drives are a less than 200 yards, this flex is perfect for you. Some golfers feel like the added flexibility provides more distance but decreases overall accuracy. These shafts are usually made of graphite.
This is the second-most flexible shaft, commonly referred to as the senior flex as it used by many senior golfers looking to bring more distance to their game. Golf shafts with a senior flex are designated by the letter "A". This shaft, made primarily from graphite, is appropriate for golfers who typically drive between 200 and 225 yards.
This is the most common shaft that is used in the game. These shafts can be made from either metal or graphite. Regular shafts, designated by the letter "R," are best used by golfers who consistently drive between 225 and 250 yards. They are for the average golfer who is satisfied with accuracy and distance and who does not want to take a chance on losing either characteristic in order to benefit the other.
These clubs are for the golfer who has very fast swing speeds and drives of over 250 yards. The flex of the shaft will be limited which improves accuracy but relies on the power generated by the golfer for distance. The stiff shaft is designated by the letter "S" and is general used by lower handicappers.
These clubs are for golfers who are the biggest hitters around. Stiff shafts will limit the amount of flex in the shaft during the middle of the swing and extra stiff shafts will take that to the next level. If a golfer with average distance used them, they would not get enough flex in the club to get the ball far enough down the fairway to play the game consistently. The extra stiff shafts are designated with an "X." Fairly rare, these shafts are used by low handicappers and some professionals.