Santeen S-T Sulfuric Acid Drain Opener- 6pk

I tried everything a desperate homeowner tries before calling the plumber, except for this. Follow the precautions. Tub drain was taking over 24 hours to drain out. I poured half a bottle of this down the drain and black stuff immediately started bubbling out of the drain, along with nasty fumes. It worked though. Didn't even leave it for the 15 minutes on the instructions. Drain was free flowing in minutes. I put the rest down the sink, which also runs great now. Don't know what I'll do with the other five bottles, lifetime supply. Really, this is acid. The precautions aren't a joke. It was actually a little scary to use. I flushed out the drains for sevral minutes afterwards, just to be on the safe side. Nothing about "being safe for pipes" on the label. My drains seem fine though. Best they've worked in years.