This cat bed is made out of plastic -- it doesn't seem like sturdy PVC, but a thinner plastic type, and you slide it through the seams of the canvas "hammock" to attach it. Then, you plug the suction cups in, and put the cat "blanket" on via velcro.
My cat loves it (see picture below) because she has a super easy visible view to where all the birds congregate. She stays up there for hours at a time, but it still isn't her favorite place to be. (That is under the bed in our guest room for some reason).
There are a couple things I want to mention about this cat bed.
First, it was so hard to put together. The instructions were horrible, but we finally figured it out as it is pretty much self explanatory, although hard to stick the plastic through the tiny holes in the canvas hammock.
Another issue we had was that one of the suctions "unstuck" from the window while my cat was on it. Luckily, I was near her and while it tilted her, it didn't make her fall. It did startle me, but she appeared unphased.
I don't know how to guarantee that this won't happen again. I have pressed the suctions hard onto the glass, but while it says it will hold 50lbs, I really don't think so. My cat is just under 15 lbs, and while it seems secure for her, I don't know if the suctions will hold in the future.
It is only $21.99 with free shipping if you have Amazon Prime so it totally is worth it if you have a cat and a good window for them to perch on!
BUY IT HERE