great toy - best toy for cats
I got the simple circuit first and bought this as a add on to the other one. They perferred the simple one without the ups and downs of the roller coaster, but this is a great toy, You will never have to look for balls and mice under the sofa and they love it. Plus you can buy add ons and change the shape of the tunnels when you want, so it's never the same and never gets boring.