I love these. I have three of them. I purchased two last summer (2019) at regular price, and one this current winter (2020) from Amazon Warehouse. I have several of my own cats, and I foster cats, periodically. As all cat people know, not all of our beloved feline friends like each other as much as we would want for them to. Not all cats mix with each other well, or even want to try - especially strays or ferals. In the last few years, I have become accustomed to using crates due to fostering as well as having litters of kittens to care for when one of my girls got out of the yard for a hot date. As any experienced cat rescuer knows, pregnant cats are moody, and once the litter has been born - very protective of their young, and even of the place in which they have chosen to give birth. Cats are territorial by nature. Even cats that generally get on well with each other will have turf wars from time to time. Add a litter of new kittens into the mix, or a stray in need of assistance, and it could be a recipe for disaster (and a trip to both the Vet and ER), depending on the temperament of the cats. I have had to separate my cats at times, and in a small apartment, there's not always adequate room to do so. The solution is to kennel the cats, in increments of time, when one is not able to adequately supervise them and keep the peace. I do have smaller crates - 30", 36", and an XXL 48" crate that I purchased in 2017 for a pregnant foster because my male cat wasn't the father of her litter - and those are great, for short periods of time. However, they are not suitable if the duration of time is longer than two or three hours. Cats can't properly move around in those, and lethargy is just as bad for their muscles as it is for humans. Not being able to move around, or climb, is stressful for them also. Kenneling in general, if for extended periods of time, causes great anxiety and depression, and can directly cause gastrointestinal problems. Crating or kenneling cats should only ever be a temporary solution, and/or for short periods of time, (even if the need is daily while one is at work), if necessary. Despite how nice the crate is, a cat cannot live in one 24-7 and never get out. That being stated, these Amazon Cat Playpens are much more suitable if one needs to crate or kennel their furbabies for the duration of a shift at work, or overnight, and/or if fostering. There is adequate space in the Amazon Basics Cat Playpen for a standard sized litter box; and, three tiers means that the cats can climb - something that all cats love to do. I have added sisal scratch posts (attached to the back of the crates) and hammocks, in addition to cozy fleece blankets and self-warming pads, onto the shelves. Bowls and feeders that attach to the sides of any wire crate can easily be attached to the Amazon Basics playpen. I have several at each level for dry food and fresh water. I have also added feather toys and hanging scratch pads (the kind with catnip in them) to a few sides, to keep them entertained when they have to be kenneled. The shelves are a perfect size for a cat to relax and take a nap on. If one places two shelves directly opposite one another, at the same height, the space in the middle is slightly smaller than the shelf, so there is room for a cat to climb in between. These shelves are adjustable, which is great, because cats of different weights and ages need space adequate to their overall body size. I stagger the shelves so there's more room to climb. To give a better idea of space: two large cats (12lbs - 14lbs) can fit comfortably in the playpen at once. Three of that size will fit, but I wouldn't suggest kenneling three large cats at once, unless it was only for a very, very, short period of time. One large cat of 18lbs - 20lbs can fit by himself/herself. Three smaller cats (7lbs or less) can fit comfortably. Five kittens of six months of age, or younger, as well as Mama cat, can also easily fit into the playpen. The playpens are sturdy, but because my cats love to climb up and on top of them, I have reinforced the sides with cable ties. I have placed cat beds and pillows atop the crates so that my cats can rest up there also. The playpens have wheels, and are very easy to move around. The wheels also lock easily to keep the playpen stationary. The shelves are good quality and very easy to remove and clean. My cats LOVE these playpens, and go into of them of their own volition, several times daily, to rest, to play, to eat or drink (when they don't feel like sitting next to one another in the kitchen at dinnertime) and to use the litter box. (I keep one litter box in each crate, at all times.) There are two doors on the front of the playpen that can be opened up separately. Since it's only my cats and no fosters at the moment - I keep the bottom door open with a bungee cord, (and the top closed) so that my cats can go in and out as they please. I only shut and lock the door when I need to shampoo carpets, or clean, or move things around in the apartment, or occasionally, put someone in time-out because he or she isn't getting along with the others . As mentioned, my cats love these playpens. I would rate the Amazon Basics playpen five out of five stars. It's well constructed, sturdy, and easy to move around. It's easy to clean and to keep clean. It's also easy to accessorize with lots of fun cat toys, scratch poles, hammocks, etc, which all crazy cat people can understand and relate to. It is also priced well, and though much less expensive than other cat playpens on the market, is just as good, if not better than, they. If you are in need of a playpen for your cat(s) - for whatever reason - I highly recommend the Amazon Basics 3 Tier Cat Cage Playpen. It's purrfect.