High Quality Content by WIKIPEDIA articles! Monofilament line is a thin string made from a single fiber. Most fishing line is made from monofilament because of its strength, availability in all pound-test kinds, and low cost. It also comes in many different colors such as white, green, blue, clear, and fluorescent. Monofilament is made by melting and mixing polymers and then extruding through tiny holes, forming strands of line, which is then spun into spools of various thicknesses. The extrusion process controls not only the thickness of the line but also the pound test of the line. Monofilament is not advisable for deepwater fishing since it can absorb water resulting in loose knots, and its sensitivity can decrease when it is wet. Monofilament degrades with time and can weaken when exposed to heat and sunlight. When stored on a spool for a long time, it may come off the fishing reel in coils or loops. It is advisable to change monofilament line at regular intervals to prevent degradation.