55cm Exercise Ball Cover, yoga ball cover, balance ball cover, birthing ball cover, 100% cotton - Black Swirl THIS 100% COTTON EXERCISE BALL COVER fits a 55cm ball. FEATURES EASY CARRY HANDLE. Have you ever tried to carry a ball while you're on the phone? Not easy! A subtle carry handle which doesn't detract from our streamlined design. LONG, HEAVY DUTY ZIP CLOSURE. Simply unzip the exercise ball cover, wrap it around your fully inflated ball and zip it up! HEALTHY HOME DECOR. This yoga ball cover is practical and adds style to a room while encouraging your family to stay healthy. Balancing on a ball makes you have to sit up straight and requires you to use your core strength. Of course, you can also use the ball for a quick back bend whenever you feel the need! OUR COVERS FIT GREAT! We've been making yoga ball covers for 5+ years and we guarantee that they will fit the specified ball size. We test every cover to fit a fully inflated ball. A 55cm ball measures 55cm in height when fully inflated. This is a circumference of 68 inches.