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 for saltwater and lure anglers. A very remarkable product.