PP again. For elementary kids, just get a jar of orange foam earplugs. But don't expect them to actually use them. My DH and all of his friends have crappy hearing now from being teenagers that were too cool for ear plugs when they were teens. But ear plugs are at least slightly cooler than actual headphones.
If you want actual headphones, ones like these are what all of the middle aged folks at rock shows are wearing.
https://www.amazon.com/Vanderfields-Ear-Muffs-Large/dp/B06XG1BSTV/ref=asc_df_B06XG1BSTV/?tag=hyprod-20&linkCode=df0&hvadid=507696750160&hvpos=&hvnetw=g&hvrand=9837786534388781955&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9061285&hvtargid=pla-349328450571&th=1