This is a must have for any dog owner with dogs who love to fetch.  This is always my #1 toy recommendation for new dog owners.  It is the best $5 investment you can make for your dog- it is my Golden Retrievers' favorite toy.  Since it isn't a chew toy, the launcher will last forever, unless you lose it :).  All standard tennis balls (2.5 inch) fit in the launcher, so you can replace the ball with any tennis ball or other chuckit! ball.  Personally, we love putting the chuckit! whistler in the launcher.  The sport launcher is the perfect size- it is small enough to toss in a bag and light enough that your arm doesn't get tired after throwing for extended periods of time.  I have tried larger sizes and found them to be too heavy and they don't throw much further than the sport.  Personally, I have 4 of these- I keep them in a dog bag we take to the park, one outside, one in the car and one in our kitchen.  Since they are cheap, its easy to stock up!  Also, it makes a great gift to new dog owners.