Coated fluorocarbon is a nylon with a skin

What the claim comes down to

Fluorocarbon is bought for one stated property: a refractive index close to that of water, which makes it less visible than a nylon of the same diameter. The corpus repeats the claim in the same words across the shelf — « quasi unsichtbar », « durchsichtig », « 100% ».

And it is sold in two forms, both honestly described in the title. Solid fluorocarbon — the listings that print « 100% » — is the material through its whole section. Coated fluorocarbon is a monofilament with a fluorocarbon skin; the corpus has one, and it is priced well under the solid leaders beside it.

No body certifies either wording. Both are the maker’s description.

What it does not promise

Invisibility is not a measurement. No listing publishes a figure for it, and the property is stated rather than tested.

A coated line does not promise the stiffness or the sink rate of a solid one, because most of its section is nylon.

Neither form promises abrasion resistance, which is what a leader is actually asked for over gravel and mussel.

And neither promises a knot strength, which is where fluorocarbon is at its most demanding and where no figure is published at all.

Where it shows up on this site

On the fluorocarbon shelf, as the first thing a page checks before comparing two prices. On the wire trace shelf, as the neighbouring decision: fluorocarbon is not bite-proof, and a pike will cut it.

It is read alongside the diameter and breaking strain pair and, on ready-made leaders, the length and whether a swivel and clip are fitted.

How it is read here

A page prints the wording the maker used — « 100 % » or « coated » — and treats them as two different products rather than two grades. Where a listing gives neither word, the page says the material construction is unstated, which on this shelf is the honest reading rather than an assumption of the cheaper one.