Voices of Service, based in Northern Virginia and under the umbrella of the nonprofit CAMMO (Center for American Military Music Opportunities), is a singing quartet that has been together for seven years. They include retired Master Sgt. Caleb Green, retired Staff Sgt. Ron Henry, Sgt. Maj. Christal Rheams, and retired Sgt. 1st Class Jason Hanna. The group uses their platform to increase awareness of what music can do for service men and women who are coping with post-traumatic stress and other invisible/visible wounds.