This exhaust is labeled '75-78 530i'. The BMW part numbers for 75-78 530i exhaust are 18121246264 & 18121246260, which also fit E24 630CSi & 633CSi, so the exhaust should fit those applications as well.

The Muffler portion was not stored in a bag and has some surface corrosion inside. The paint inside the tips is flaking and one of the yellow stripe decals on the tips has mostly peeled off. The slip fit on the muffler section does not have marks from being clamped, so this was never installed.

Dual inlet ID: ~41mm

Single pipe ID: ~47.5mm

Please let me know if you have any questions,

-Alex