Ultra-high-molecular-weight polyethylene in the context of "Dalton (unit)"

Fiber (spelled fibre in British English; from Latin: fibra) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.

Synthetic fibers can often be produced very cheaply and in large amounts compared to natural fibers, but for clothing natural fibers have some benefits, such as comfort, over their synthetic counterparts.

Multifilament line, also referred to as The Super Lines, is a type of fishing line. It is a braided line which is made up of ultra-high-molecular-weight polyethylene (UHMWPE), a specialty polyethylene polymer that makes an extremely thin line for its strength. By weight, UHMWPE strands are five to ten times sturdier than steel. Multifilament line is similar to braided dacron in terms of sensitivity but a diameter about one-third that of the ubiquitous nylon monofilament line.

Multifilament works best on conventional and baitcasting reels. On spinning and spincasting reels, the line's limpness can make sure for awkward manipulation, as it does not "spring" off the reel like monofilament. Consequently, knot-tying is more difficult with multifilaments. Certain knots work better with superline, like the palomar knot. Applying a type of super glue will help to prevent other types of knots from slipping.