In fly fishing, fish are caught by using artificial flies that are cast with a fly rod and a fly line. The fly line (today, almost always coated with plastic) is heavy enough to send the fly to the target. The main difference between fly fishing and spin or bait fishing is that in fly fishing the weight of the line carries the hook through the air, whereas in spin and bait fishing the weight of the lure or sinker at the end of the monofilament or braided line gives casting distance. Artificial flies are of several types; some imitating an insect (either flying or swimming), others a bait fish or crustacean, others attractors are known to attract fish although they look like nothing in nature. Flies can be made either to float or sink, and range in size from a few millimeters to 30 cm long; most are between 1 and 5 cm.