Unlike gas-pressured balls Vicky's rubber balls won't lose pressure over time and have more bounce. They are ideal for beginners & sports enthusiasts and work efficiently with tennis ball machines. They are a flexible addition to your tennis practice equipment as they can be used on any court whether it is hard or soft made of clay or cement. You may use this rubber ball for a variety of things rather than just playing tennis. It can be used to train your pets or you can use it for playing gully cricket matches.