Bat

Question
does a bat have to be a certain regulation size or weight for high school play?

Answer
Yes, in high school baseball, there are weight and size restrictions on bats.  There are 2 options.  The first one, which is almost never seen, is that a player may use a wood bat, with barrell diameter no bigger than 2 3/4" and a weight differential of no more than -3 (for instance, a 33" 30 oz bat is ok, but a 33" 29 oz bat is not).  The other more popular option are metal bats.  Metal bats may only be a maximum of 2 5/8" in diameter and carry the same weight differential of no more than -3.  For metal bats, they also have to meet certain safety tests requirements, but any metal bats that meet the other requirements will always have had these tests done.  I hope this answers your question.  Please leave feedback if you can :)