The Auto-Swivel AGS Yoke allows for multi-angle adjustments while safely locking instrument in place. It can accommodate a wider range of instrument neck sizes from 40 mm – 52 mm (1.57 inch – 2.05 inch) including classic, acoustic, electric and bass guitars. The attached N.I.N.A. (Narrow Instrument Neck Adjustment, HA301) are specially designed to increase the thickness of AGS arms to accommodate narrow neck instruments from min. 28 mm (1.10 inch) like banjos and mandolins. Screw-in standard wall mounting system.