This boxwood recorder is a copy of an instrument by the famous maker Johann Christoph Denner (1655-1707). It has the same range of two and a half octaves as the alto (treble) recorder.
The voice flute is a recorder in d.
Denner's original instrument may have been a very high pitched tenor, rather than a
real voice flute, which was a fairly special instrument with a wonderful low register, but a range of no more than one octave and a sixth, and only a small repertoire of its own.
Modern voice flutes and tenor recorders are often used nowadays for playing music written for the transverse flute at actual pitch.