I have the API 550b 500 series EQ, which provides surgical notch eq with the punch and transparency API has always been known for. Masterfully craft, with carve or boost, the perfect sonic shape on the way in. Brings life to everything from kick drums, bass guitars, and pianos, as well as adds air or space to a lead vocal. I'm the original owner and this unit is in mint condition. Has been in my studio in an official API lunchbox only. This unit retails new for $1100.75!Dan