Official promoter-issued 2nd printing 28&3/8 x 20&3/8" uncut pair of concert posters for Big Brother & the Holding Company (with Janis Joplin) appearing with Oxford Circle on 8/5/1966 and Bo Diddley appearing with Sons of Adam on 8/6/1966, both shows held at the Avalon Ballroom in San Francisco, CA.

 Art by Alton Kelley with Stanley Mouse, image is # 19 in the Family Dog/Avalon series.

 Medium-thin flat index stock poster is in very good (B/B+) condition; there is a 2" diagonal bend and creasing in the lower left corner, along with a few small edge tears/dings and a couple of hairline-thin bends scattered around the outer margin area and a few stray handling creases/tiny pin-prick scuffs here and there, otherwise fine.

 Neat-looking double-uncut pair of 1966 Avalon posters.