ProBody Pilates Small Exercise Ball – 9 Inch Workout Ball for Stability, Barre, Yoga, Core & Physical Therapy

Customers find the exercise ball to be of good quality, easy to inflate, and suitable for various activities including physical therapy knee exercises and yoga. The size is perfect for exercises and stretching, and customers consider it good value for money. Regarding durability and air retention, customers have mixed experiences - while some say it seems strong and stays inflated, others report that it doesn't hold air and can cause damage to furniture.