A downrigger is a device used while fishing using the trolling method, which places a lure at the desired depth. A downrigger consists of a three to six-foot horizontal pole which supports a cannonball, generally 10 to 15 pounds, by a steel cable (generally stainless steel or wire). A clip, also known as a "release," attaches a fishing line to the cannonball weight. The bait or lure is attached to the release. Operation of a downrigger Downriggers consist of four major components, the weight, cable, pole or boom, and the spool. A fishing line is attached to the downrigger cable by means of a "line release." The weight is normally a five-to-twenty-pound mass of lead which is connected to the stainless steel cable. The spool is brought up either by a manual crank or via an electric motor. In addition to attaching a lure to the fishing line, an oval piece of metal or plastic (often hammered or curved for reflective purposes) called a dodger or flasher is often used to attract fish from greater distances. The types of lures used to troll with using downriggers range from metal "spoons" that are often decorated using color tape or paint, plastic or rubber "squids", tinsel beaded flies, or painted plastic J-plugs. These all come in a variety of colors, finishes, and glow patterns for various fishing conditions. The length of fishing line between the downrigger release and the lure is known as the "lead" and this varies in length depending on how far behind the boat the fisherman would like to lure to trail. This fishing line is typically between ten and twenty pound test. When fishing for salmon this lead is often quite lengthy in order to avoid the fish being frightened by the noise of the boat's trolling motor. When many boats are trolling in a small area this often results in crossed lines and tangles which are a detriment to the fishing experience. The speed at which the lure is pulled through the water has a great impact on success or failure. For this reason fishermen use devices that accurately track speed. Typically, trolling from one to five knots is the range that allows for fish to be caught. This varies from species to species as Chinook Salmon may prefer higher speeds while the more docile Lake Trout may prefer a much slower-moving lure. Trolling motors are used