12 color plates in a printed envelope.
During the production of Russ Cochran's Complete EC Comics Library, the printer ran off extra sheets of the color covers. After the books were bound, Cochran took the extra sheets, had them trimmed, and produced these portfolios of EC Comics covers.
These prints are the exact same covers used in the COMPLETE PANIC, as such, they are on the same glossy stock, and printed on both sides--the cover on one side and the inside front cover on the other side, however these are trimmed to include the entire cover and a white border.
From the publisher:
The twelve covers contained in this envelope represent some of the finest artwork done for EC comics. These are the same covers used in the COMPLETE PANIC, except that they are trimmed to include the entire cover. The artwork, mostly by editor Al Feldstein, was colored especially for this series by the original EC color artist, Miss Marie Severin.