The tub top cat gym is the best selling cat tree in the kitty gym series and its not hard to see why. This all around cat condo has a great variety of activities for your cat or even for multiple cats. It has a strong and wide wobble-free based that measures 24" X 24". Its a terrific cat tree to put next to any window and features multiple cat trays for kitty to observe from or sleep in!  The large tub top at the top measures 16" in diameter and the two other tubs measure about 12" in diameter.  This model also comes with a 16" Swinging triangle that measures 16" X 16" X 16". Each tub curls around at 4" at the lip.  A great feature about this model is that all the wood posts you see are lined with sisal so they are all sisal scratching posts. This will make sure kitty will scratch his cat tree and not your own home furnishings!