I've recently bought one of these and they work extremely well. I've got an Arai Quantum st-pro which has speaker pockets and they fit like a glove. The sound quality is excellent and is still auidable at 3 figure speeds ( as tested on a track day officer !!) I bought this due to the fact there is nothing clamped to the side of your helmet, everything is hidden inside the lining.
A good buy for anyone interested !!