Crazy for core? Get back on the swissball and churn out those moves with this essential stability companion.
To nail the perfect sizing, plant both feet on the floor with knees positioned slightly lower than the pelvis.
If you see a nice 90 degree angle, crunch on.
High density rubber construction for longevity
Anti-burst technology for slow and safe deflation if punctured
Weight can influence flexibility and resistance, so size appropriately
