A leaf blower (often referred to as simply a blower) is a gardening tool that propels air out of a nozzle to move debris such as leaves and grass cuttings. Leaf blowers are powered by electric or gasoline motors. Gasoline models have traditionally been two-stroke engines, but four-stroke engines were recently introduced to partially address air pollution concerns. Leaf blowers are typically self-contained handheld units, or backpack mounted units with a handheld wand. The latter is more ergonomic for prolonged use. Larger units may rest on wheels and even use a motor for propulsion. These are sometimes called "walk behind leaf blowers" because they must be pushed by hand to be operated.
Some units can also suck in leaves and small twigs via a vacuum, and shred them into a bag. In that role it is called a blower vac.