It works just as advertised!
Had previously used some top of the line drain cleaner - which used to work.  Saw Professor Amos on tv and thought it looked too good to be true.  Tried it and was immediately pleased.  Used it in two bathroom drains, one which was very clogged overnite and it was fine the next morning.  The other put the liquid in the drain, waited 15 minutes and it was clear.  Would recommend it to all.  Do plan to purchase to have on hand all times.
Rating: 5 stars