The Etymotic ER-20 are a set of universal fit ear plugs, designed for uses of all types. I have used the ER-20s during concerts as well as during band practices. I should say that I no longer use the ER-20s even though I still own them, as I have upgraded to a pair of custom fit Westone ES49 ear plugs. However, I did use the ER-20s frequently for a few years before getting my custom fit plugs. The ER-20s served me well in the time that I used them, as they did a good job of blocking out sound and were pretty comfortable to wear overall. The should fit well into just about anyone's ears, as I never had a problem getting them to fit comfortably. The only thing that I don't like about the way they fit is that they stick pretty far out of your ears while they are in there, which is more annoying than anything else. The ER-20s come with a small case as well as a piece of string to hold them together, which I never had a need to use. While the ER-20s do a decent enough job of blocking out sound, you can't hear everything all that well while they are in. So beyond just wanting a more comfortable set of ear plugs, the main reason that I got custom fit plugs was because they are much better at making it so you can actually hear what is going on around you, just at a much lower volume. So while the ER-20s will do the job for blocking out sound, if you're a musician or a frequent concert attender, I'd recommend spending some money to get proper hearing protection where you will be able to still hear all of the individual components of a sound. However, if you're just looking for some cheap ear plugs I'd definitley recommend the Etymotic ER-20s as the first place to look...