The jumbo tennis ball is made of a basketball inner core and will require being pumped up before play. Pump is not included. For best results pump until firm. PRODUCT DESCRIPTION Watch the excitement on your best friends face when you surprise them with this giant tennis ball. Measuring 9.5 inches, the tennis ball is made of a basketball inner core with a thick felt layer. This jumbo ball will provide countless hours of fun for your pup and is the perfect gift this holiday. The jumbo tennis ball is made of a basketball inner core and will require being pumped up before play. Pump is not included. For best results pump until firm. PRODUCT DETAILS 9.5" Tennis Ball Basketball Core With Tennis Felt Outer