The HandMaster Plus hand exerciser helps strengthen hand muscles. The HandMaster Plus can be used to treat carpal tunnel syndrome, tennis elbow, golfer's elbow, RSI's (repetitive stress injuries), tendonitis, DeQuervains' syndrome, Dupuytren's contracture, osteoarthritis, osteoporosis, stroke, neuropathy, post-surgical rehabilitation, sprain/dislocation/fracture rehabilitation, subluxation and adhesion, and circulatory concerns. This exerciser combines flexion and extension. Instructions included. There are 3 levels of firmness available: soft (purple ball, yellow cord), medium (red ball, black cord), firm (orange ball, gray cord).