Powerful, works great!
These work much better than the round ones. Great results for me (gets rid of hot night feet). However, I only got 6 (30-min) sessions out of it over 6-month period until covered in rust. Used minimal salt at first (gradually increased after first few times). Water very hard with high mineral content in my area and only cleaned after each use by rinsing thoroughly after each time. Was expecting each unit to last 10-12 times at this ($50 price for two)...but...still tons cheaper than a spa ionic foot bath visit ($45+tip).
Rating: 5 stars