Kluson gold toplock Vintage 6L in line tuner with oval button. The "Kluson Toplock System" allows locking the string from the front of the headstock. The slotted locking screw can be tightened with a coin and presses on a little steel ball, which gently locks the string inside the shaft. The tuners also work when the locking function is not used. This Vintage edition Kluson "Toplock" tuners are great upgrade for Vintage Hotrod projects.