Wow I just spoke to the owner what an amazing and nice man I am going to try and help him by posting a link on my Facebook page Cheers DougAfter years of development, Karl Ahrens, of Mountain Ocarinas, has recently released the "Coda EDC Flute", which is an extended range, dual-chamber ocarina instrument. "EDC" means "every day carry," to convey the important point that Coda is designed to be a durable and portable instrument that you can have with you all the time without fear of it warping, cracking, breaking, etc.
You can find out more at https://codaedc.com/ and https://www.youtube.com/channel/UCxDHcWirn6i1OoFY7ECfa7g.
I'm not affiliated with the company except as a friend and "test pilot," as well as a player of Mountain Ocarinas for quite a while. I've played a number of Coda prototypes over the past few years as Karl worked to arrive at a design that both played well and could be affordably produced and sold. Coda is significantly more complex than the usual ocarina, or even the usual dual-chamber ocarina.
For one thing, Coda does not require the player to move the fingers of one hand to a different set of tone holes when switching chambers. He or she need only switch windways; the fingers stay put. In addition, there's overlap between the two chambers, which means that B5, C6, C#6, and D6 can be played on either chamber. Although this is a bit daunting for the new player, it turns out to be a huge advantage as you get used to the instrument. It gives you more flexibility with respect to when to switch chambers, which can help a great deal with phrasing and overall playability of certain tunes.
The two chambers are an octave apart, and the C major scale is fingered the same on both. Some of the other notes have different fingerings in the two chambers, similar to the way fingerings vary on a recorder. Because this is an ocarina-type instrument, all notes are played as fundamentals or first harmonic. Consequently there is virtually no risk of squeaking or note-splitting, as can occur in the higher registers of a recorder. All notes on Coda are "pure."
The actual range is C5 to C7, fully chromatic. In addition to the chamber overlap I mentioned, there are alternate fingerings available for many notes. Again, this isn't something a new player would bother with, but as you gain familiarity with the instrument it can be a real advantage.