This is amazing. The shower was stained when we got this house almost 4 years ago. I am very OCD about my house and have spent countless hours scrubbing with everything I could find, natural, chemicals, etc. and nothing worked. I ran across these brushes and love power tools. In just 15 minutes with a natural vinegar, water, baking soda and dawn mix, the icky stains are gone!!! I will definitely be a repeat customer.