I have been using them for a long time about 8-9 years. I get tested every year for hearing loss by my company. I have had little to none as far as loss. I use a company that makes the mold of your ear. precision labs
Products they make them for all kinds of applications ipods, tactical, shooting. I have a few sets just in case one is broken. I just send one back and ready to go with the other. I dont fly without them. I use to fly with the volume all the way up and now its just cracked open. not cheap but good quality.
Dave