Leipzig, Bibliographisch Institut, [1913]. Oblong mount and text leaf (25.5 x 33.8 cm), with fold-out full colour cutout with additional flaps. In original printed envelope (26.2 x 36.0 cm).

This is an "Einzelmodelle aus Blücher, Moderne Technik", a series of pop-up and foldout plates showing complex mechanical structures, how they look and how they work, in great detail, in this case a "U-Boot", or submarine. If completely unfolded, the submarine is 55 cm long. Other items in this series, e.g., Diesel engine, Zeppelin, airplane, etc., are listed on the front side of the envelope. Tear in the envelope, weak crease in the lower left corner of the text leaf and mount; otherwise, fine, the submarine itself, with all its parts, beautifully preserved.