The most common 'size' is the D flute (cover all 6 holes and it plays a D). There are also flutes in other keys, such as C and E (a longer and a shorter instrument, respectively) that give the player access to keys other than those normally played by a D flute, letting the player use the natural fingering patterns and ornaments, while the flute transposes the tune for him into the desired key. The stongest keys for a D flute are D, G, C (major keys), a, e and b (minor keys). Having a C-flute then, lets the player access keys such as g minor or d minor, playing the tune with a minor or e minor fingerings, which works much better. Flutes with keys, however, let you play in most any key you please, something I've found useful when exploring Swedish folk music or playing with pipers, but the ornamentation gets more difficult once you leave the "strong" keys of the instrument.

There are many fine makers of Irish flutes out there. From personal experience I can heartily recommend instruments by Rod Cameron, Patrick Olwell and Terry McGee (not necessarily in that order). All make instruments of superb sound and quality.

Sound clips, samples from recordings I'm on. Some tunes I've written. Henrik Norbeck, another Swede who plays irish flute. Chris Wilkes, maker of simple system flutes. Beautiful photos! Terry McGee, flute maker, a great information source. A Guide to the Irish Flute by Brad Hurley Ceolas tune archive Swedish folk tunes