It's about 20 inch diameter by 12.5 inches high. My full grown cats that are each 11 pounds fit in there. Especially my big fluffy guy.

They both could sleep in it if they are small cats. This is one of the larger kitty condos that I own.

Hi Julie45, you are an Angel for taking in this cat after your cruel neighbors left her behind. There are insulated/heated cat tents and houses for outside use and you can google them to find one with the best price. It's unfortunate that the cats don't get along. I have two cats that used to hate each other so I had to keep them separated on different floors in my house for a while until they got used to each other. I used a tall gate at the bottom of the stairs rather than put either one outside as I live in the Northeast and the winters are freezing. If you aren't in a position to separate them in your house and you want to keep this sweet cat, you could always call the Animal Rescue or ASPCA and they will give you some solutions for helping the two cats adapt to each other. The other thing is, if you ever feel you can't keep the additional kitty, you could ask one or both of those places to refer you to a true "no kill" rescue that will take her and find her a good home. We have some wonderful places in Massachusetts that help with this.... Hope this helps.

I find the easiest way to clean fur off carpeted cat items is with water... a damp cloth, paper towel of even your hand dampened with water, will easily roll the fur into a ball for a quick toss to the trash.

sorry 6 and half inches is not a big enough opening for a large cat. my cats are all 17lbs or larger. i dont know why they make these so small. my cat gets clastaphopbic.

I don't know the exact dimensions but the opening is large enough for a large cat.