Not enough contact and too slippery with soap to work
I looked for negative reviews and found none and I did note all positive reviews are from their website only.
These stones don't have enough surface contact with your skin to work. As a sphere, there is only a tiny contact surface with your skin. I did not note any silkiness or smoothness after using them for a bit and using them with soap is actually quite difficult (and has very little to no friction). I question their design, but also the material. One fell from a very great height and clay would shatter. This didnt even dent. I would recommend finding another product and method. I tried to post a review to their website and found no way to do so - smells scammy. I also emailed them to inquite about why I was offered the duo slate bases for 9.99 but when I added them to my cart it read 15.99 with no way to change this. They never replied.