These earplugs are made to reduce volume without affecting the quality, ideal for clubs, concerts, raves, etc. They're meant to attenuate frequencies equally, in practice it's not quite flat but it's pretty good. These are a great product at an excellent price to use in loud environments. Once you damage your hearing you can't get it back, so prevention is much better than the non-existent cure. I've had mine for a couple of years and they work as well today as they did when they were new.