So I've had this unit a while but only got chance to try it recently with some concentrates. First used with some crumble and it performed pretty well, decent vapour and taste..got a few hits from a very small amount. I allowed the bowl to cool slightly and got left with a carb mark in the middle which kind of taints the taste of the bowl now. Second tried with some sticky shatter...good flavour and effect..the session lasted longer with this material and gave more vapour too. This definitely gives a decent dab style hit in effects..of course it's never going to produce huge clouds and flavour like a rig but I suspect this device would be closer to a real dab on a rig than a pen device? Edit: vapefiend supplied new metal o-rings but noticed when changing the stock ceramic one and dropped it it broke into two pieces..