Review (4/5): I think the unit could be a bit more powerful.
During the pandemic, my feet got incredibly rough. I spent more time walking barefoot around the house, and my pedicurist was closed for months. I decided to trying doing my own pedicure. I think this Wonder 4 will do a nice job, but it is taking some "getting used to." I had to experiment with the different grinding heads to determine which worked best on my feet. I think the unit could be a bit more powerful. But, it does smooth rather quietly. It just takes a little longer than I expected to receive "professional-like" results. The rechargeable battery makes it very convenient. It is supposedly for wet or dry use, but I have only tried it dry. I feel that smoothing would take even longer if I added moisture.