Advanced ergonomic "S" shaped back massager helps ease muscle tension and reduce pain in soft tissue, and increase range of motion and overall function. Used by hooking over shoulder or under an arm to apply deep pressure to trigger points in the muscles of the neck, shoulders, upper and lower back. Approx 9" to 11" x 22". Lightweight, durable, and compact with built-in locking (take apart for easy storage and travel). Comes with a 35 page, fully illustrated User Guide.