The stratosphere (/ËstrÃ¦tÉËsfÉªÉr, -toÊ-/) is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. About 20% of the atmosphere's mass is contained in the stratosphere.
The chainsaw is a highly effective and efficient tree and branch cutting power tool. It works with an engine, referred to as a power head; powering a metal chain, driven by a centrifugal clutch, with a chain moving around a groove in the guide bar at fast speeds.
chuck - a holding device consisting of adjustable jaws that center a workpiece in a lathe or center a tool in a drill. handwheel - control consisting of a wheel whose rim serves as the handle by which a part is operated. handwheel - a wheel worked by hand.