This is a set (3 on a side) of genuine Grover Imperial tuners in chrome, part number 150C, new and blister packed. Gear ratio is 16:1 with a die-cast, one-piece housing for additional strength and precision. The unique bearing surface in the housing provides a rigid string post that enhances the alignment of the gear and worm. Post hole size is 25/64" (.391). The classic imperial button makes this a perfect choice for restoring the looks of that vintage guitar of yours. All necessary hardware and screws are included. Upgrade that guitar with some new, old looking hardware today! No modifications necessary. These come with a lifetime factory guarantee. Return to Grover for a free repair or replacement.