Aria Pro II Integra IGB-550 PJ Passive Bass 4 String BassNotes Believed to have been made in the early 1990s. Control knobs have been replaced. A Aria Pro II Integra IGB 550 PJ Passive Bass 4 String Bass in Very Good condition! At Evolution Music, we attempt to highlight cosmetic defects (if any) by picturing every angle of every piece of gear so you know exactly what you are getting. We always picture any and all accessories too. What you see is what you will get so please check out the pictures!