This is the new locking version of the standard Tune-O- Matic bridge that secures solidly to your guitar and won "t come loose or fall out when the strings are out. This TonePros System II bridge is the same that you will find installed on the top new guitars direct from the factory and will look identical to your stock piece because it "s made from the actual OEM bridge used on your guitar, but the new version locks in solid creating perfect intonation and singing sustain. You won "t believe the difference, and you will never go back! This model fits your Gibson Les Paul, SG, 335, as well as most other USA Made Guitars. Bridge Stud Diameter: 4 mm, Smooth Top Bridge Center To Center Spacing: 2.913 , But With A Slightly Larger Hole To Accommodate Any Difference Saddle Spacing: 10.4 Mm