Recorders are a whole different kettle of fish. Tin whistles, pennywhistles, flageolets (trust the English to come up with a name like that and then expect us to say it with a straight face) can be aluminum, tin, brass, chrome plated nickel, wood, plastic, and maybe other rarer metals, like the ones used for flutes.
They are diatonic, that is to say they basically play in one key, though some modified fingering will get you the occasional sharp or flat.
Compared to recorders, they are simpler. Cover all six holes (on the front, no back hole)and you have the tonic ordo. Lift your fingers, one at a time and you go up the scale. Six holes give you the six notes between do and do, which brings the total to eight. Want the second octave? Blow harder.
So you want a different key? Pick up a different whistle. The Generation comes in A, Bb, C, D, Eb, F and G.
Yes, a G whistle is kin to a sopranino, but the latter is much more genteel. Actually, I think the recorder has more overtones than the whistle, and that makes it less, uh, invasive. Whistles sound more like fifes, if you are familiar with them.
Try checking out the webpage in the link above for more complete information.
Blessings,
Barbara