Jackhammer Headphones
These are about like a pair of headphones that my dad made back in the early 70s.
Unlike the Bose model, these block outside noise instead of cancelling it. Listen to music or books on tape without hearing traffic noise, screaming babies, etc. I’ve been making these for more than a decade. People sometimes ask “isn’t it dangerous not being able to hear?” No. Talking on a cellphone shuts off most of the brain whereas listening to headphones is no more dangerous than say, being deaf. Lots of my friends use these units and no harm has come to anyone.