Adapter bushings to retrofit US ¼ inch post Kluson tuners in a headstock drilled for modern die cast tuners. Nickel plating. Set of 6. These Kluson® steel replacement - adapter bushings are intended for use in converting a modern 10mm drilled headstock to accept a vintage Kluson stamped steel tuning machines with the original US ¼ inch string post diameter. Many repair shops use these to convert a vintage instrument back to original peg head specs