Surprisingly good for the price
This is a surprisingly good product for the price.  I'd had a similar one that used AAA batteries, years ago,  but water and batteries ultimately resulted in corrosion and it stopped working.  This one had a rechargeable battery that charged by USB.  It's still on the first charge after a couple weeks.  I keep it in the shower and use it daily. Only improvement I could recommend is a larger water reservoir.
Rating: 4 stars