hey! I have a full set of Gold Grover 3 per side tuners for sale. These are the Paten Pending Grovers. I beleive the circa was pre WWII (world war 2) I am taking SERIOUS offers! These things are as rare as they come. The pioneer of guitar tuners!@ TYhe first in its class ever made! let me know! I have alot of references! thanks everyone! Peace and Blessings!!