This is a full size gold replacement button for Grover Rotomatics (102 Series). Many tuners for guitar, ukulele, banjo, mandolin, and dulcimer have buttons on their tuners that can be replaced. Replace a worn, pitted or discolored button or replace the whole set to give your instrument a new or unique look. These are also sold individually in my other listings. These measure 7/8 inch in length, 5/8 high, and 5/16 inch thick at its middle. The screw hole is 7/64 inch diameter. The shaft diameter is 9/64 inch. These are interchangeable on Grover Series 102 (Original Rotomatics), 106 (Locking Rotomatics), 109 (Super Rotomatics), 150 (Imperial), and possibly 205 (Mini Rotomatics), 406 (Mini Locking Rotomatics) if spacing permits.