This is a really rare part that you can find on a few Gibsons in the very early 80s - 1982/1983.
Check out my history video on these here
youtube.com/watch?v=tXVnMRihJjg
This was a new bridge design that Gibson was making where you could adjust intonation from the top and the bridge with 9 different positions that it could sit on the posts with. This made it so Gibson could use the same bridges on both left and right handed guitars. This idea was quickly discontinued so these were only offered on a few select models. The models you can find these stock on are The Explorer E2, ES 345, ES 355, and the Victory Series of guitars. Some The Paul / The SG models and Flying Vs also got them. There are also a few of these that can be found on Les Paul Customs that still have the slots for 9 positions, but don't have the top adjust saddles.
This rare part is in good vintage shape. The B string screw is very worn, but still usable. It has scratches and light pitting. This one has nylon saddles. Only the bridge is available, no studs/posts.