Choosing the right tennisball
There are basically 2 types of tennis-balls: pressure- and pressureless balls. Choose depending of the surface:
Pressureless tennisballs
These balles are ideal for soft surfaces like artificial grass. Somewhat less comfortable, they do keep their bounce longer and tend to last longer. Pick for example the Tretorn Plus 4 of de Tretorn Plus 3.
Pressure balls
For gravel and other harder surfaces. After some time the bounce will decrease, and the ball will react differently. Pick the inexpencive Dunlop Max TP4 or the more sustainable Wilson US Open.
Junior trainingsballs
For the young beginners Wilson offers 'slow' trainingballs, wich makes it easy to play the ball back. Pick the Stage 1 or the orange-yellow Winners Stage. | 
