A grapple is a hydraulically powered claw with two or more opposing levers that pinch cement or other materials, usually to lift or drag them. A grapple can be mounted to a tractor or excavator with a movable arm that may lift, extend/retract, and move side-to-side (pivot or rotate). Some machines also have a separate control for rotating the grapple. Simpler grapple machines consist of a hydraulically liftable fork or bucket and a movable, opposing "thumb" (one or more hooks or levers) that enclose and grip materials for lifting or dragging.