Focus the mind and aggression of your would be champion improves hand eye coordination features durable pu punch ball on sprung chrome bar base is filled with water or sand to hold in place the junior adjustable free standing speed ball is able to grow as your child does this is so that your child will be using the junior adjustable free standing speed ball at the right height this is so they don t cause any injury to them or damage to the equipment specification of the junior adjustable fr