HERCULES GSP39WB PLUS GUITAR WALL HANGER METAL
part no: GSP39WB PLUS
This is the one with the metal back plate. The GSP38WBPLUS is the wooden backed version also available.

Description:
The HERCULES Auto-Swivel Yoke Hanger GSP39WB PLUS rotates automatically to accommodate different shaped guitars or basses vertically and safely. It features a screw-in standard wall mounting system.

Features:

The Upgraded 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” – 2.05”) including classic, acoustic, electric and bass guitars.
The attached NINA (Narrow Instrument Neck Adjustment) are specially designed to increase the thickness of AGS arms to accommodate narrow neck instruments from min. 28 mm (1.10”) like banjos and mandolins.
Screw-in standard wall mounting system.