This backing track helps you practicing a chromatic descending sequence of Major Seventh Chords. You can use this backing track for many purposes, but one goal would be to be able to play non stop the looping sequence, and master your scale or chord changes descending chromatically.
Here you can download the audio file for free:
This is and image of the recorded sequence. Left for Eb instruments, center for Concert Instruments, and right for Bb instruments.
Practise also II-V-I minor progression backing track