Purchased at the end of 2022 and used at home. There are scratches from rack mounting when changing racks. Operation has been confirmed, and this is a single unit sale. Although not consecutive serial numbers, I have another unit that was introduced at the same time, so those interested in stereo use should also take a look. I will offer a discount on the shipping cost. ① Type: Microphone preamplifier / DI Standard: API500 Sounds like an Old Neve from Rupert Neve Designs.