Peanut Massage Ball - Double Lacrosse Massage Ball & Mobility Ball for Physical Therapy - Deep Tissue Massage Tool for Myofascial Release, Muscle Relaxer, Acupoint Massage. ✮Perfect Design For Comprehensive Massage✮- 5" in length and 2.5"in diameter, weight in 12oz. This split peanut shaped massage ball is a perfect design to get to those hard to reach stabilizing muscles that surround your spine and vertebrae without applying pressure on them as you lay on it. ✮Durable Material✮- The massage ball is made of 100% natural rubber, which is firmer than tennis ball, but not like the hard plastic balls with knobs and they hurt. It is durable for long-lasting use.