Finally got my hands on one of these units. You may recall my thread on the HMMWV bracket available for this extinguisher. The unit uses compressed air from a SCBA bottle to create foam from a tank full of a water/foam concentrate. The foam is then blown 30 feet from the nozzle. The foam can be generated for about 30 minutes which should allow someone to extinguish a good size fire. This would be perfect for someone living far away from first responders or someone living in an area prone to wildfires. Mibot LLC fixed me up with this unit at a good price.