... 32 sizes :2.5inch,3.5inc Rubber SPARQ Eye Reaction Ball,rubber Reaction Ball1. Best for reaction training, ... abiliy with the irregular rebound direction. The Reaction Ball is ideal for agility training either individually, ... ability to track objects in motion. Four durable rubber nodes guarantee a dynamic unpredictable bounce. Excellect ... doubt,demand,please contact me. rubber SPARQ Eye Reaction Ball