A user interface for an electronic trading exchange is provided which allows a remote trader to view in real time bid orders, offer orders, and trades for an item, and optionally one or more sources of contextual data. Recoil forces cause the high pressure cylinder 7 and barrel assembly 2 and 4 to move relative to the sleeve valve 8 opening communication between reservoirs 9 and 11. The liquid chocolate includes solid particles suspended within the liquid chocolate.