My cats love these balls in the rail

About 3 months ago I bought 2 packets of rails and assembled into a 8.
My two cats have indeed touched the ball a few times, but did not have much interest ...
By Customer Rating I then became aware of the luminous balls and since then the rail is the absolute favorite toy my puss! Throughout the day will be chased by the rail of the ball. By tapping once he gets so much momentum that it creates and 2x 8 all the time Jaden afterwards both cats. Any other toy (fishing, balls, mice, etc.) has become uninteresting and they both deal with it very well alone.
The only downside: while watching TV or phone (and at night when the room with the rail in earshot) you have to take them the rail, because the roar can be quite annoying :-)
However, the balls have a different level of sensitivity ... One of the balls already lit when time a truck has passed in front of the door and the batteries were accordingly quickly empty. The current ball must be already triggered quite tight so that it lights up and the cats find much more interesting.
My personal conclusion: I bought the rails and now 2 complete sets (incl. The glowing balls) given away to other Katzernbesitzer (with the same resonance) and would recommend it to anyone cat owner immediately!
Currently I'm waiting again on a new delivery balls for my sister ;-)