This is an awesome product, you will definitely want to use a firm rubber mallet OR a metal mallet with a towel as a buffer. I only had to use a mallet for the 2 side panels and otherwise it was super easy to install. I didnt have the problem of pieces being bent from the shipping like other buyers. I use this for 2 foster kittens at a time, and love that this has the option to be extended for more kittens or for a larger play area. I got this one because the ferret style cage has a smaller opening if you buy a second upper unit. 

Pros: Easy to clean, sturdy, powdercoated, has wheels, durable, big enough for kittens. 
Cons: Be careful moving when it first arrives, box is heavy!