The silver 30" two way gym ball is excellent tool to strengthen your core muscles,the muscles located in your pelvis, lower back, hips and abdomen. Strong core muscles can help prevent poor posture, lower back pain and muscle injury. Specification : Anti burst. Flat and knobbed surface offers two

The silver 30" two way gym ball is excellent tool to strengthen your core muscles,the muscles located in your pelvis, lower back, hips and abdomen. Strong core muscles can help prevent poor posture, lower back pain and muscle injury. Specification : Anti burst. Flat and knobbed surface offers two way body workout. Excellent for body workout and tension release.