Hercules's AGS (Auto Grip System) Yoke safely grips instruments as they're loaded in, up to 2.01 in width, and features a metal mounting base. Included with the GSP39WB Plus is the N.I.N.A. (Narrow Instrument Neck Adjustment) accessory, which accommodates necks as narrow as 1.1 inch — hang your ukulele, banjo, mandolin, or violin with confidence. For looks, security, and ease of use, Sales Engineers stand behind our Hercules GSP39WB Plus wall hangers.