my 8 year old dog loves to play catch but it has been hard to find a ball that she won't destroy but is practical too. Living in Michigan, the winter has been fierce. This collection of balls has it all, one ball whistles when you throw it so she watches and listens to it intensely to find it in the snow. When I get home late for work and it is dark I bring out the ball that glows and we have so much fun in the dark! Can't wait for spring but this has made winter more bearable for us!