OK the "Best Ball Ever" is what my dog would say. The flashing balls are the only ones my dog likes. I''m not sure if it’s because of their weight, texture or smell. She will not play with tennis balls, or similar plastic balls. There are 2 problems with them. #1 If you dog only likes the flashing light, the battery cannot be replaced in them. I''m not sure how long the light does last, but it’s possibly a month or two. My dog doesn''t care; she just likes types of balls. #2 They are not durable for heavy chewers. If left alone, even my dog will totally chew these up. These do float, (even after there are a few chew holes in them) and have a little bit of bounce to them. They are durable enough for me to play street hockey with them, and I have hit them with a baseball bat. With my dog who is not a heavy chewer, (she will drop the ball on command) and has to play with these almost daily I get about 6 months of use out of one of these on average. That is not counting the flashing light. I have had some last over a year before they are chewed beyond recognition.