I took the concertina apart, and was very impressed with the internals of the action box. It has parallel reed pan construction with handmade steel reeds mounted in brass frames. The action is quick, smooth, and responsive. The notes speak immediately which attests to the quality and workmanship of the steel reeds. It has a pleasant harmonious sound.
Chords sound with a nice resonant effect.
The resonant effect was an unexpected, pleasant surprise when I first heard it. Colin told me that this would get even better with time, as the instrument gets broken in. I am also pleased with the balance, e.g., the volume between the left hand and right hand notes. All rights reserved. And if you do, the least you could do is give me a link and credit.