For me and my hearing, no better than $1 foam earplugs
I recently tried this at a fairly noisy show at Austin City Limits.  I found they did not work for me at all to improve fidelity.  They reduced the sound somewhat but the net effect was no better than $1 foam earplugs.<br /><br />If I were you I would forget these and try some disposable plugs.  You pocketbook might be happier, along with your ears.
Rating: 1 stars