This official Gibson Wired ABR-1 Tune-o-matic bridge is based on the vintage bridges originally introduced in 1962 which added a retaining wire across the intonation screwheads on the front of the tune-o-matic, this wire was added to stop the saddles from falling out of the bridge during string changes. It also features the vintage style 'GIBSON ABR-1' and foundry mark casting on the bottom of the bridge and standard ABR-1 specs like bridge posts that screw directly into the guitar body that make the originally ABR-1 so iconic. The narrower ABR-1 body width is compensated for by the two reversed saddles on the bass side for extra intonation room (all saddles are reversible) and the saddles come unslotted to allow them to be filed to the correct string spacing and gauge for your guitar.