Ideal for pelvic floor exercises, the ball will enhance your Pilates workout and help develop strength, endurance, and concentration as well as to promote relaxation and coordination. The balls are anti-slip offering excellent grip. Ball size is down to preference though it is common to have both sizes for greater diversity. Features 12" Exer-Soft Ball (30cm). Ideal for pelvic floor exercises. Enhance your Pilates workout. Help develop strength, endurance, and concentration. Promote relaxation and coordination. Anti-slip offering excellent grip. Size: 12" (30 cm)