Is this Chicago's greatest single? That's actually a rhetorical question... they had so many different styles over the years it's hard to compare them. Certainly, this is their best in the hard-rock/psych style. That opening bass line is unforgettable! And though the label doesn't say it, this is a beautifully edited version of the over-long, 4:50 album cut. This is a copy of the pressing with orange "Columbia Records" against a red background. Note: This copy comes in a vintage Columbia Records factory sleeve. The labels grade Near Mint. The vinyl grades EX, reflecting some scuffing indicative of jukebox play. Fortunately, the audio remains undistorted and almost totally without surface noise, grading Near Mint.