NYDA Physio Ball - 55cm

Heavy duty PVC exercise ball, burst resistant to 350kg. To select the correct size you should measure your sitting position to the ground while your knees are at a 90 degree angle. Sit slightly higher if using your ball as a desk chair.Recommendations:
Height over 180cm - 75cm ball
Height 168-180cm - 65cm ball
Height 156-168cm - 55cm ball
Height under 156cm - 45cm ball