Used it for more than one hour without a problem. I love that I can adjust it without taking it out. Super easy! And thanks GROOV for your service and fast shipping as usual!
I play in brass bands and groups and these earplugs do not really deliver the advertised quality I would have expected for the price. Disappointed. Maybe no-one considers brass instruments when manufacturing or designing these???
These earplugs do block sound out just fine, but as a singer the effect is similar to all other earplugs, it's very hard to gauge pitch and tone with these in. Bit disappointed.