Review (4/5): TWO YEAR WARRANTY!
The three most important words regarding this product is its TWO YEAR WARRANTY. Compare that to other similar products and buy with confidence.
The rest of this feedback I'm aiming at the guys, since it's hard to believe any woman would let her feet get as disgustingly calloused as we men would. Guys, the question I bet is at the top of your list is "How powerful is it?" I'm not gonna lie - to really get rid of thick callouses is going to require patience. Powered by four AA batteries, the spinning head-wheel goes at a good speed, but if you give the unit anything more than moderate pressure against your foot, the wheel will slow or stop. That means you'll need to do longer sessions with lighter pressure. But it DOES WORK! Just don't expect to get to your goal of socially-acceptable feet after five minutes of usage. I've done three 15 minute sessions just on one foot and I'm very nearly there.
Other than that, I'm happy with this unit.