Great for my cats.  I usually put one cat in at a time because they don't like to be close together.  It's good for where I live with the heat. I actually bought TWO of these.  I had the smaller one, but since I sometimes put 2-3 cats there, I just bought the larger one. 

 The house gets hot and when they go into the "tent" (that's what I call it)  they feel more comfortable and I can see them catching the breezes.  It took awhile for them to get used to it, but now they know it's a place to cool off and look around the yard.  

I have two of the cats now in the yard in the new, larger pet playpen.  They seem very happy to catch some cool air and just hang out.  I love these!!  And so do my cats!