These stands can be used on any surface that is relatively flat, so the fan doesn't fall out. They also don't have to be positioned in any particular way, either. If you have a very skinny flat surface you want to put them on, say maybe a kitchenpass-through or nook, to hold up the fan, but don't have the ability to turn the fan in that direction, simply toss these on in the center and you can turn the fan any way you want while the fan remains upright.
eBay