I have tried it through my cleaning company and it do's not work as it states.
Yes it cleans the glass, but no it would not remove hard water build-up, calcium, lime stains and rust stains from a shower this doesn't it's expectation.

My car's windscreen had developed vertical streaks that made it impossible & dangerous to drive when it rained. I don't know where the streaks came from and my car is only a few years old. Other cleaners made no difference. This product "polished" the windscreen... just like new. Clean, perfectly clear and beads beautifully when it rains.
Worked as promised
Takes a little "elbow grease" to apply and remove, but worth the effort.