Grover Professional Mandolin Machine Heads 309FVN, Vintage 4 + 4, For &ldquo;F&rdquo; style Mandolins, Nickel F-type Deluxe Vintage Mandolin Tuners 18:1 ratio, Nickel with Pearl buttons, Worm under gear Designed by master luthier Lynn Dudenbostal Item Number: 309FVN Available at Ant Hill Music!