Please note that the balls need to be used on an even surface for wall work, and on sufficiently impact absorbing training mats for floor work for the warranty to be valid. The balls may get damaged from high impact on an uneven surface, or on sharp edges of an uneven wall etc.
D-Balls/Slam Balls are a great tool for all kinds of training. Often used for rehabilitation and strength training, it serves an important role in the field of sports medicine.
They are used effectively in plyometric weight training to increase explosive power in athletes in all sports.