I have an interesting Jones concertina on Ebay:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...E:IT&ih=008
It is the first I've seen with the double thumb button on the left hand. It has a Jeffries-style parallel reed pan layout unlike other Jones I've had. It's in C/G. Making way for a Jeffries G/D.
