The Reflex Ball OSU is the perfect training accessory for working on hand-eye coordination and reflexes. Great for training even when you're at home and don't have a sparring partner. The kit consists of an adjustable velcro headband, 4 balls with elastic offering different levels of difficulty, and spare elastics. Additionally, the kit includes a bag to store the Reflex Ball OSU, so you can always take it with you. The package also includes instructions for use and training tips.