So useful. I looked a long time to find one that is sturdy, well built like the one I have had for 10 years at the back door. Now I have one at the front and back door. They are able to get the find dirt out that gets stuck in the cracks of my walking shoes by New Balance. I use it by placing my toe of one foot on the first bar to hold the unit and then do the bottom brushing with the other shoe. I do not stand on the brushes as that will bend the bristles causing it to not work as well.