The 1926-29 Exhibits "Postcard Back" issue is speculated to have been issued in the Philadelphia area.  Though the cards typically feature postcard backs, they are occasionally found blank, and some with the notice "Not for use in Exhibit Machines."  Further, some contain a country of origin (USA) added to the backs.  The cards can be found printed in a variety of color tints as well.  The result is a wide variety of possible variations with differing degrees of scarcity, very appealing to advanced hobbyists.

Black and white portrait of Hall of Famer Paul Waner, an attractive early card with outstanding eye appeal, the VG/EX 4 grade assessed due to light wear at the top left corner, and some mild surface staining on the reverse.