This wheel is fantastic, and very easy to build,I slowly built it over a fews day, and kitties where always around watching what was going on, and I intoduced them to the wheel built and lay flat on floor, jumping in and out, and over it, next I put carpet on, and lock on wheel, again so they get used to it, still in process of getting them to get on it and move wheel, but they will get there, all in all, its a fantastic size for my kitties, who are 5kg and 6kg, its also very lightweight, so can be moved easily from room to room if need be, I especially like the locking mechanism on it, so when I have to leave house, i can put lock on it so I know they wont hurt themselves, its all about the 🐈🐈🐾🐾