CELLF is working, sooner or later you will use it too @CELLF is working, every morning I climb the stairs, it's 11 floors. Timing , heart beating and how I feel during climbing the stairs is good indication of progress. I get to the top 40% faster, heart beating didn't change, I don't feel dizzy or shortness of breath when I get to the top. Few days ago I got too fast to the top, I got shortness of breath but it wasn't that painful like that last couple years I've had.
Everybody else will use it, of course if they know that it's on the market already.