I've had quite a past of abusing opiates, had a 3 bag a day heroin habit for awhile. All kinds of pills and shit, and fentanyl is something I've never even dared think of doing. It's usually called China White on the street, and it is a synthetic opiate that is somewhere around ten times for powerful than heroin, and there are fentanyl derivatives that are even more powerful. Actually I did think of doing it, that would be a hell of a ride. Be careful. I'd say stick to heroin.