The 70mm acrylic contact ball is the most popular for multi-ball tricks or single ball manipulation for those with small hands. Acrylic balls have minimal friction with one another making stacking tricks a lot more pleasurable. All our contact balls are 100% acrylic. Acrylic balls are incredibly strong but can become scratched if repeatedly dropped on rough surfaces. These balls come supplied in a neat cardboard box. All our contact balls are 100% acrylic.