The ball test looks impressive, but in the real world, cfm is the name of the game. When you constrict air in a tube you are only using mph, not cfm. I have never blown an area twenty feet long and cleaning only the size width of a small ball. In the tube and ball test, a smaller cfm but larger mph looks impressive, but real world test tells me to look for the most cfm for your cc size of blower. 600 cfm w/ 200 mph will blow wider and farther than a 480 cfm w/250 mph. The ball test is an old salesman's trick that looks good. Trust me, cfm is the name of the game! WIDER AND LONGER GETS YOUR JOB DONE FASTER!