Rotec, HSS Hand tap set, 2 pcs, DIN 2181, UNF 3/4"-16

UNF 3/4"-16 x 11mm square.
HSS hand tap set in UNF fine (Unified National Fine) thread. DIN 2181. Set includes 2 taps. consisting of 1x plug/bottoming tap and 1x a taper tap.
Used for cutting internal imperial threads (UNF fine or UNC coarse), like commonly used in the USA.
Note: The 'square' size is diameter of the shank, for checking size compatibility with the jaws of hand-tapping wrenches.