Kluson SD91MLNL 6 Oval On-Plate Guitar Tuning Machines, Nickel Kluson, replacement machine heads for Explorer, and Non-reverse Firebirds Nickel Screws and push fit bushes included Key measurements - Post to post distance - 15/16, E to E distance - 4 9/16, Length of baseplate- 5 7/8, post height- 1 1/16, drilled, single hole