Germany, NSFK. An Aero-Modeling Achievement Badge, Type II visually-hidden in silvered zink

in silvered zink

the other is present but has broken off)

WWI German U-Boat Group - U-Boot Badge

in a u-shape

also earned by the 1st Battalion)

Germany, NSFK. An Aero-Modeling Achievement Badge, Type II visually-hidden in silvered zink(NSFK Modellflug Leistungsabzeichen 2. Modell). Constructed of zink, the obverse consisting of a circular oak leaf wreath, joined together at the bottom by ribbon, overlaid by a glider passing through a cloud, the reverse with a barrel hinge and horizontal pinback meeting a round wire catch, stamped with an award number of 0042, measuring 37. 80 mm (w) x 36. 28 mm (h), weighing 12. 5 grams, demonstrating loss of finish throughout the base metal, a