Monofilament with high light visibility in all weather conditions. Transparency in immersion, on the other hand, is equivalent to that of nylon because the polymerisation with fluorescent additives is supplemented with percentages of polyvinylid fluoride, a polymer with low refraction (1.33). The brightness obtained from the reflection of external light is gradually cancelled during immersion by an indirect refractive effect, which transforms the fluorescence into a transparent neutral colour. This type of compound also increases the linear and knot resistance and the specific weight of the monofilament, and consequently also the sinking capacity.