A cubic foot of air per minute through any device (blower, compressor, etc) is 1 CFM. That same amount of air, even after it is compressed, is a Standard Cubic Foot (even though it takes up less room than 1 CF after being compressed). 1 CFM and 1 SCFM are the same amount of air if there is no compression (i.e you are not squeezing the air into a pressurized tank). 1 CFM is more than 1 SCFM if you are talking about the outlet flow of a compressor that is discharging into a 100 psi tank. Compressors are commonly rated at X SCFM at Y psi (for instance 9.5 SCFM at 120 psi). Leaf blowers are rated simply with CFM ratings (for instance 200 CFM). Therefore, when you are talking about a leaf blower, you talk about CFM. The air is not compressed; it is just moved. You should look for a unit with a high CFM rating as opposed to a high speed rating. When you are talking about an air compressor, you look for a high SCFM rating, as this compensates for different outlet pressures. I hope this helps, but I don't know where your question is comming from. Here is a picture of my eight-legged cat at suppertime.