The maximum air volume or CFM is the amount of air being pushed out of the leaf blower. The air volume is the best indicator to measure the power of a leaf blower; this measurement differs from maximum air speed or MPH because the speed indicates how fast the air is moving and not how much. A higher CFM means the leaf blower is more powerful. Within DEWALT Leaf Blowers, the maximum air volume (CFM) ranges from 100 - 200 to 500 or Greater.