This set of large massage balls (4 inch diameter - just a little smaller than the Trigger Point MB5) is designed for large muscle groups like the shoulders, chest, back, glutes, and hamstrings and is made from EVA which is soft enough and firm enough at the same time. We offer free instructional video to all, on our website and full phone support. Watch them and learn to do your own trigger point therapy, acupressure and deep tissue self-massage. Excellent for myofascial release which is your first line defense against tendinitis and other chronic muscle and tendon pain including RSI, tennis elbow and more. These myofascial release balls make great gifts for your athlete / yoga friends or anyone looking for a large firm massage ball set. Get relief when you need it, not when your therapist has an opening... Deep Recovery (formerly Massage Track) is your ticket if you want to release tight muscles safely and easily using the same physical therapy tools / techniques employed by the best therapists and chiropractors.