The Auto-Grip Violin/Viola Wall Hanger from HERCULES Stands slides directly into a slat-wall mounting system to easily hang your instrument. Simply place your violin or viola in the yoke, and the Auto-Grip System (AGS) safely locks your instrument in place by utilizing the instrument's weight to engage the grip system. Specially formulated foam on all contact points protects your instrument's lacquer from dents and scratches.