Ive found that its much easier to lose a single fan to withering away, rather than a double fan, even if the fans are small. I guess if you could actually see a picture of the fan you are getting, it would be easier to buy. I know some single fans can be huge. One I got was a single, but you could see how it was going to explode into 3 or 4 in a month. I really dont understand offering a single spider fan. Those things arent big anyway, but grow like weeds. Ive got about 4 clumps of spider fans that Ive got to split up this month, and I groan to myself every time I look at them.