This is a UNIQUE Die Trial set of four different German denominations struck in copper and uniface. These are the reverse strikes for the 50 Pfennig, 10 Pfennig, 5 Pfennig and 1 Pfennig.
Several German Numismatic reference books list several of these die trials struck in copper, lead and silver but only of a single die trial strike. These were struck and presented to King Farouk circa 1950 for his personal coin collection. The mint mark is J for Hamburg, Germany.
The surfaces are proof with extremely deep mirror fields. A spectacular German rarity with a famous pedigree and is unique.