This is a remix of the common Ear protector out there. I wish I could give credit to the original creator but there are so many I don't know who that is!
Anyway, most of them have 8 hooks and longer than necessary.This one has just 4.

My wife is a nurse and I've already printed dozens of them for her and her coworkers. That's after I printed dozens of the original for them and took their notes that it was too big/long.