I knew when I ordered this, one would not be enough!  I should have known our 3 cats would have a hard time taking turns sunning in such comfort! They absolutely love this thing!  I'm not one that can easily put something together just by reading the instructions, but I think even a child can figure this one out!  It's sitting very securely on the window sill using only the braces, and the extra soft cover has made it their #1 spot in the house.