A duck call may be either the sound-imitation process by which a hunter lures waterfowl, or the actual tool which the person uses to do so. Early duck call tools were basic woodwind instruments, while later innovations are constructed of rubber and plastic, and allow the hunter to adjust the volume and tone of the calls with reeds. Today's duck calls usually fall into three main categories: single, double, or triple reed call with many variations, although the triple reed is rare. The goal of a duck call is to sound like a realistic live duck, in attempts to decoy, or fool a duck into believing the decoys that are seen by a duck, and the sound that is heard appears lifelike.