Description: The HERCULES Narrow Instrument Neck Adjustment (N.I.N.A.) HA301 are specially designed to increase the thickness of AGS arms. Features: Accommodates narrow neck instruments (like banjos and mandolins) and different neck sizes from min. 28 mm (1.10"). Suitable for plus series guitar stands & hangers (e. g. GS414B PLUS) Find a Dealer tweet share