What is the difference between a single-hose system and a dual-hose system?

With a dual-hose blast system, the dry ice travels in one hose and the high pressure air in another. They are not mixed until just before they exit the nozzle.

Single-hose blast systems mix the high pressure air and the dry ice from the time it leaves the machine. Single-hose systems can at times be the better choice when needing a more aggressive clean.