Original 1st printing 11 x 16&7/8" concert poster for Mountain with Humble Pie (featuring Steve Marriott and Peter Frampton) and Eric Mercury at the Boston Tea Party (15 Lansdowne Street location) in Boston, MA on 11/20-22/1969. Art by Eric Engstrom, medium flat index stock poster is in excellent to near mint (B+ to B+/A-) condition; just a well-camouflaged moisture stain in the top right side of the top margin, a small 1" bend in the lower left corner, a slight pinch ding in the left center margin, otherwise fine. Really nice-looking late '69 Tea Party poster with a cool design and an interesting lineup.