Baseball bats MUST have either a USA Baseball, BPF 1.15, or BBCOR 0.50 sticker on it for it to be valid for game use. Which bat hits the best? Generally speaking, a BPF 1.15 have more pop than a BBCOR 0.50 (generally only used by bigger 7th graders and 8th graders anyways), which will have more 'pop' than a USA Baseball bat. Will Taylor started the "Bat Bros" on YouTube. Bat Bros does a FANTASTIC job of reviewing individual brands of bats on their videos.
A bat's weight in ounces is the same as the length in inches minus the "drop". For example: a 30 inch drop 10 has a weight of 20 ounces. See the chart below for suggested lengths. Common guidance is a child should be able to hold the bat with their dominant hand straight out at arm's length for 30 seconds without lowering it. We suggest not buying a bat that your child can 'grow into'. Bat speed depends on mechanics but also strength. An excessively heavy bat has to be gripped farther up the handle which reduces the reach.