FPC Sport Pack of 4 tennis balls, model #50304. These all-purpose balls are made of durable felt and will allow you to play on all surfaces. You'll benefit from a soft, hollow, air-filled rubber ball coated with a tough felt to give you a durable design that's strong when in use. These tennis balls are multi-purpose and can be used for multiple purposes such as hockey, baseball, lacrosse, school, dogs, etc. The product include: One tube of four tennis balls. Get new quality tennis balls at good prices for your multiple daily uses.