This boxwood recorder is a copy of an instrument by the famous maker Johann Christoph Denner (1655-1707).
The voice flute is a recorder in d, a fairly special instrument with only a small repertoire of its own.
Denner's original instrument may have been a very high pitched tenor, rather than a
real voice flute. It has the same range of two and a half octaves as the alto (treble) recorder.
Voice flutes and tenor recorders are often used nowadays for playing at actual pitch music written for the transverse flute.