Gap bumper is a must have if you have a dog! It took us 1 minute to install and gave our dog endless playtime. Our pup is kind of like a cat - she seats the balls and runs back and forth to chase them. This meant a lot of us getting down on the floor to fetch the ball for her. It was such a hassle we eventually said no balls in the house. Since we installed gap bumper, she’s been a very happy pup!