On an electric blower or a variable throttle on a gas-powered blower, these let you increase power for sweeping on hard surfaces or open ground and decrease it around fragile garden beds.

The first time I used the Stihl BR 600 ... powered backpack blower that I have used. The blower boasts 610 cfm and up to 180 mph, making it more powerful than several gas-powered backpack blowers ...

On an electric blower or a variable throttle on a gas-powered blower, these let you increase power for sweeping on hard surfaces or open ground and decrease it around fragile garden beds.