Cover a wider range of massage for your neck, body and back with this Adjustable design. Our massage balls feature a textured spiral surface, which stimulates blood and oxygen flow for total muscle relief. Its anatomical design fits the body's natural curves for an effective massage experience. Simply find a tense or knotted muscle area on your body. Then, adjust the massage balls for a custom fit. Gently roll the balls along the area of tension for 30 seconds, then rest. Or, pull the balls completely apart to reveal the green Acupressure knob inside, which can then be used to apply direct pressure to an area of tension. Anatomical design targets both sides of spine Adjustable width for customizable therapy connected design for stability during use end knob to target specific areas.