Treb, the Sub Sterling USA model was made alongside the Ray Subs but had a shorter build run I think so not that many in circulation. A strange beast, 3 band active EQ but no switching like the full fat US Sterling. Also, it has 22 frets like a Sterling but is a 6 bolt neck rather than a 5 bolt. They don't come up often used, I think they are typically £450 - £500 for a decent example.