Paul it's a MIDI Bass loop called Jazzy Rock Bass 01. Logic Pro 9 comes with about 50 gigs of loops, MIDI and Audio. The cool thing is the loop browser where you can audition loops live , they even play in the key of the song in audition. It's like a bigger version of Garage Band. Still not as Cool as Biab's Real Tracks though, this song would have been boring without the drums and their fills and the Sax. Thanks for listening Paul!