A stability ball is a versatile rehab and training tool used by physiotherapists to improve core strength, spinal stability, balance, and postural control. The TheraBand Pro Series ball is made from burst-resistant rubber and inflates to 26 inches (65 cm), making it suitable for adults between 5'7" and 6'1". For climbers, it is useful for core activation exercises, lumbar stabilization work, and shoulder rehab drills that require an unstable surface to challenge neuromuscular control.