This is a classic that will never get old. My cats love this product, as do my kids. The ball rolls really smoothly, if my kids would leave it alone, and my cats love to chase it(or watch it with evil intent from under the nearest chair).
Whoever created this product needs to be shot. Not only is the size much too small but the stress a male betta experiences when he can see another betta is astronomical. The stress alone can cause holes in the fins from too much flaring and sickness. Add in the ridiculously small amount of water which would get toxic fast is basically a death sentence for these amazing and majestic fish. Do not get this. It's a waste of money and it's cruel to the fish.
While the packaging is fairly convenient this product is essentially fillers with a tiny bit of protein. Do yourself and your betta a favor and read the ingredients of the food you buy him/her! If the first ingredient is anything other than actual fish, put it down and get something better.
This product is dangerous to all fish with a labyrinth organ(Bettas are included this group). It contains an oil that coats the labyrinth organ(the organ that allows them to breathe air) and harms them. I have experienced as have others, that after using this product a betta tends to die. please do your research and do not use this product on any Labyrinth organ fish!