Mitsubishi Shaft Profile Guide
Butt Flex: If you’re a hard loader or pull the shaft down hard at the top of your backswing, you likely need a firmer handle section to hold up to the strain you’re placing on the shaft.
Mid Flex: A firm midsection usually creates more activity in the butt or tip sections. If you like feeling some activity on the edges of the shaft, look for a firm midsection. Some shafts are firm throughout, usually to hold up to higher swing speeds.
Tip Flex: A firm tip will help stabilize the head during your swing, but likely at the expense of some feel. The softer the tip section, the more you’ll be able to feel the head during your swing.