This is a set (3 on a side) of genuine Grover Rotomatic(R) "Milk Bottle" tuners in nickel, part number 102NV, new and factory packed. The button style is a vintage style found on Les Paul guitars and others. Gear ratio is 18:1 with precision cut worm and gear for perfect meshing, eliminating backlash and slippage. Gearbox is permanently lubricated and countersunk tension screw permits the player to regulate the tuning tension to custom feel. Post hole size is 25/64". They are a perfect replacement for your existing tuners. All necessary mounting hardware, bushings, and screws are included. Upgrade your guitar with some new tuners today, and enjoy easier and more accurate and stable tuning for a change! No modifications necessary in most cases. Take off the old ones, put in the new. These come with a lifetime factory warranty.