Shimano Ocea EX Flourocarbon Leader
The construction of the Ocea Leader is also extremely unique in that it features a hard outer shell for abrasion resistance, a fluorine coating on top for a clean surface finish, and a soft fluoro centre for knot strength.
It is transparent in colour, thinner than comparable breaking strain nylon, extremely abrasion resistant, doesn't absorb water to sink more quickly, and has a refractive index that is quite near to that of water, making it less apparent to fish.