I thought I would give a bit of an update review after using the ACS t-15s for a while now, you can read the previous review here. Well this is a bit of a mixed review, probably based on a rather horrible experience I had with them...user error? Perhaps, although I am not sure! I brought the T-15's to slot into my ER molds, but on one occasion I decided to simply use the supplied ear pieces. To cut a long story short, they both came off in my ears and I was seriously considering having to go to casualty to get them out as they wouldn't budge, if it wasn't for the sterling efforts of our sound engineer Tracey and our singers tweeters, I think I would have ended up in hospital. I am not ashamed to admit it was rather scary.Having said that, when they are inserted in my molds, they sound really great, maybe slightly lacking in bass, which only a 2 driver unit would supply, but I just have a small amount of guitar a vocal in my mix to fill in the gap in frequencies which are removed by the ear plugs. So the level over all isn't loud at all and this works really well for me.Another little problem, they have on occasion popped out of the molds, which is a really shame and also a problem when rocking out, as you have to fumble around to reinsert the ear piece. My other complain is that the earphone/mold combo is difficult to get out of the ear without dismantling.To be honest...I probably wouldn't go with this combination again. I am actually tempted to get a new pair of molds and then get these glued in somehow.If you have any questions, just let me knowPeaceNeil