ADJ F4L QD Quick Dissipating Fog FluidThe F4L QD is specially formulated to quickly dissipating after its projected out of a fog machine. It has been designed to work like a CO2 effect when used with the ADJ VF Volcano, Fog Fury Jett and Fog Fury Jett Pro. Using the F4L QD with one of ADJ's vertical fog machines is a great, cost effective alternative to expensive CO2. The F4L QD comes in a 4 liter container and is a safe, water based fluid approved by the FDA.