Fab toy, but could do with being harder to dismantle!
We have 3 cats: the oldest non-playful one just ignores this toy completely, but the other 2 can't get enough of it. I've laid 2 circuits out together in a figure of eight, and put both balls in at once. It keeps them amused for hours. The beautiful but dim pedigree cat uses it as it should be used - just sending the balls round & round the track, and being delighted when the two of them collide and spin off in different directions. The much cleverer moggy kitten has sussed how to dismantle it and hoik out the balls, which she then bats under the sofa, where they stay until we can fish them out again & put the toy back together... It could be vastly improved by making the guards click really firmly in place.