The first instrument was built in Edinburgh and had a separate pipe for each pitch. The second instrument was built by Flight and Robson in London, and used moveable shaders close to the mouth of the pipes in order to lower their pitch temporarily by one or two commas which reduced its cost and size, and with an improved bellows the system was the subject of a patent granted to Liston and Charles Broughton on 3 July 1810.
The first instrument was built in Edinburgh, featuring individual pipes for each pitch. The second instrument, crafted by Flight and Robson in London, employed movable shaders near the mouth of the pipes to lower their pitch temporarily by one or two commas, reducing its cost and size. This innovation was further enhanced with an improved bellows system, leading to a patent granted to Liston and Charles Broughton on 3 July 1810.