This is an aged Nickel Tone Pros® Nashville Tune-O-Matic Bridge TP6-N.  Here is a brief description of the bridge: 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 off when the strings are removed. Components are the same as those that you will find installed on all the top new guitars direct from the factory. Hardware fits Gibson® Les Paul®, SG, 335, as well as most other USA-made guitars.