the rod and mainline helps to cap the transferred stress and protect those more costly gears/tackles from overloading and breaking (similar to how a fuse protects a circuitry), which will minimize loss and cost of repairs/replacements if the fish manages to overpower the angler's gear setup. Tippet or trace is used occasionally in fly fishing, and serves as a secondary leader that thread to the much smaller and delicate fly hooks. History Early lines Leonard Mascall, in his book from 1596 titled “A Booke of fishing with Hooke and Line, and of all other instruments thereunto belonging.” followed in many ways after Dame Juliana Berners, has an excerpt establishing silk worms in the area of England at that time: ... ... And another excerpt explaining compiling a silk leader-line for a catgut fly-line. So back then there was silk and horse hair used for angling. As written in 1667 by Samuel Pepys, the fishing lines in his time were made from catgut. Later, silk fishing lines were used around 1724. Modern lines Modern fishing lines intended for spinning, spin cast, or bait casting reels are almost entirely made from artificial substances, including nylon, polyvinylidene fluoride (PVDF, also called fluorocarbon), polyethylene, Dacron and UHMWPE (Honeywell's Spectra or Dyneema). The most common type is monofilament, made of a single strand. Fishermen often use monofilament because of its buoyant characteristics and its ability to stretch under load. The line stretch has advantages, such as damping the force when setting the hook and when fighting strong fish. On very far distances the damping may become a disadvantage. Recently, other alternatives to standard nylon monofilament lines have been introduced made of copolymers or fluorocarbon, or a combination of the two materials. Fluorocarbon fishing line is made of the fluoropolymer PVDF and it is valued for its refractive index, which is similar to that of water, making it less visible to fish. Fluorocarbon is also a denser material, and therefore, is not nearly as buoyant as monofilament. Anglers often utilize fluorocarbon when they need their baits to stay closer to the bottom without the use of heavy sinkers. There are also braided fishing lines, cofilament and thermally fused lines, also known as 'superlines' for their small diameter, lack of stretch, and great strength relative to standard nylon monofilament lines. Braided, thermally fused, and chemically fused varieties of 'superlines' are now readily available. Specialty lines Fly lines