Beachbody P90X 65-Centimeter Grey Textured Pro Grip Exercise Ball, Increase Overall Stability And Strengthen Core Muscles, PX1380GY 65cm diameter grip ball with 1mm embossed texture This professional quality grip ball is ideal for improving strength, power and speed in the wrists, fingers and forearms Ergonomically designed and appropriate for all gender hand sizes, seniors, and teens Non-slip textured surface is covered with soft, comfortable and durable rubber for frequent and comfy usage