JOOLA Outdoor Balls are especially designed to withstand playing in a variety of outside conditions. Ideal for outdoor playing, these balls are made to last through cold, heat, UV rays, and humidity. They are 41% heavier than standard indoor table tennis balls to counter windy conditions and are water resistant for playing in the rain and bounce as well as indoor balls. Start playing like a champion with equipment developed for champions by JOOLA, proud sponsor of the US National Team.