This is the new locking version of the standard Nashville Tune-O-Matic with the newly-developed G-Formula saddles. This new formula is improved over the original synthetic saddles that were used on Gibson® instruments dating back to the early 60"s. The formula has been redeveloped and is vastly superior in both life and tone. Would you expect anything less from TonePros®? TonePros® bridges are designed to secure solidly to your guitar and not come loose or fall off when the strings are removed adding both security and sustain. This model fits your Gibson® Les Paul®, SG®, ES-335® as well as most other USA made guitars.