What does a flex index on a softball bat mean?

Answer 1

The number itself means nothing, it's an arbitrary number made up by the manufacturer. The important thing to know is Miken, Easton and DeMarini are the major manufacturers which offer 2 flexes in the handles. Basically, the stiff handle is for players with faster swing speeds and the less stiff handle is for players who need more whip to improve bat speed. There is diminishing return if you have a fundamentally sound swing and use a regular flex handle - the barrel head will lag behind.

So, if you are a power hitter get the stiff flex handle. If you're not, get the regular flex handle.