Derek Hobbs, author of The Piper's Companion series tells me - In my quest to encourage duet and trio playing of Northumbrian pipes I have prepared demonstrations of all 240 arrangements in the Piper's Companion series and hope that this might be an easy way to get some idea of how the arrangements might sound. Although these arrangements were first conceived for Northumbrian pipes, they are very suitable for other instruments - I have heard from quite a number of concertina players who like to play the duets in these books. http://derek367.wix.com/rossleigh-music I've used them a lot myself. Bryan