Proteus was developed by Ultima’s team of world class internationals specifically for anglers who want that edge in clear waters and testing conditions. Proteus is 100% pure fluorocarbon and therefore not only sinks twice as quickly as normal mono but is also effectively invisible in water. Proteus has been designed with a medium/high stiffness for precision presentation in hard conditions when every bite is critical. With its very high knot strength and superb abrasion resistance, Proteus is the perfect fluorocarbon. A very remarkable product.