I've used these at the local hookah bar and i have to say aside from a few times when they rolled off the bowl and landed in the tray, they are great, they don't burn too hot and burn the shisha and they don't produce a whole lot of ash compared to quick lights.
I have been using these coals for about a year now and they have been great, but then the last one I purchased I tasted a funky taste. I pulled out one of these coals and found a rubber piece sticking out of it. It kind of looked like a rubber band.
I am not sure if this was suppose to be in them but I really don't think smoking rubber is a good thing.
I love these!! Pulled out one of these coals and found a cool effect i cant explain but you really need to see
good coals nice and hot but they roll off the bowl