This is the rarely seen third season promotional advertisement. Mostly, this 8 1/2" by 11" promo was given to advertisers as a way to let them know how many episodes were available for ad space through season three. This ad was circulated to the agencies just before season three began.
To take a larger look at either side of this promo, click on the images above. You will note that Kari Wuhrer is not pictured or mentioned (since she was still a glimmer in Fox's eye at this point) and more interestingly that David Peckinpah was given highest billing of the Executive Producers even at the beginning of season three.