contact with fish or bait is more direct. It is often used for deep water fishing from boats because lower diameters are used, which give less resistance to currents, and the low stretch makes bites easily detectable. Specialty lines Fluorocarbon line Some modern monofilament lines are made from polyvinylidene fluoride (PVDF), a fluoropolymer often marketed as fluorocarbon. Fluorocarbon lines or "fluoro lines" are valued for their similar refractive index to that of water, making it less visible to fish, which may not swallow the bait if it sees the line. Fluorocarbon lines have greater surface hardness than nylon lines and are more abrasion-resistant against underwater rocks and snags, yet are more shock-resilient than braided lines when fighting fish, thus making them ideal to use as leader lines especially when the mainline is braided. They also have less memory, stretch and moisture expansion than nylon lines, making it easier to keep the line taut and transmit vibrations, which is essential in lure fishing where the angler is very reliant on tactile sensitivity. PVDF is also a denser material and therefore not nearly as buoyant as nylon monofilament, and anglers often utilize fluorocarbon lines when they need lighter baits/lures to sink more quickly and stay deeper below the surface without using heavy sinkers. Copolymer line A newer type of modern monofilament lines are composite lines that are fused from two different substrates via a process known as copolymerization. Most copolymer lines are nylon-based polymer blends, fusing a blend of nylon with another higher-density one. Compared to conventional nylon lines, copolymer lines have much higher test weight (strength) especially for small diameters, have less stretch, and are more abrasion-resistant. They are stronger than fluorocarbon lines per diameter but also less rigid, which makes them more shock-resilient and knot-friendly, although also more susceptible to wind-knotting (entanglement of loose loops of line). Like monofilament lines, copolymer lines tend to sink slowly in water, and are better suited for lure fishing near the surface (e.g. dry fly fishing). Some copolymer lines are additionally coated with fluoropolymer (trademarked as "FluoroKote") to give more fluorocarbon-like surface property and to change the refractive index, as well as to also allow faster sinking as the added fluoropolymers are generally denser than nylon. Use Monofilament fishing line is used in a huge variety of fishing applications. Monofilament is not advisable for deepwater fishing, since it can absorb water, resulting in loose