Gave this single shoe warmer/dryer to my sister-in-law who moved here from South Carolina.  She has two dogs and has to go out in all kinds of weather.  This shoe dryer/warmer is essential to keeping her head on straight.  I did trip against some shoes in the dark and fell against these things which ripped my upper lip, so don't go around in the dark and expect these things to remain benign.  Apart from that event, they are great.  They do dry slower than the kind with fans, but they are soundless, and that is important.