Item Type: Reaction Balls Material: Rubber Product Weight: Approx. 138g / 4.9ozPackage List 2 x Reaction Balls 1Rubber Material: The irregularly shaped ball is made of thick rubber, which is strong and durable. 2Two Styles to Choose: The reaction bounce ball feels comfortable, there are two different types in one set, which can be used according to your preference. 3Main Function: The random bounce mode of this reaction ball can improve hand eye coordination and reduce reaction time. 4Mini and Portable: Small in size and light in weight, the reaction ball is easy to carry, very convenient to use. 5Widely Used: As an exercise appliance, the reaction ball is used for speed, agility, strength, running, football, volleyball, basketball, baseball, football and all other sports, fitness, weight or cross training.