Thank you for viewing. This is a Prescription Electronics octave fuzz. It's one of my favorites, but I don't use it much, so I'm selling it to someone who will. The serial number is unknown as it is not listed. No LED, with an adapter jack. It is believed to be a 90s transitional model, with only the jack added for practicality to the initial model. I rarely use the swell mode, and during the operation check, I didn't feel the gradual swell described in the manual. It's unclear whether this is a setting issue, a malfunction, or just how it is. The item is for sale as the main unit only; no box, manual, or adapter are included. Jimi Hendrix Tokyo Jihen