Proteus has been developed by Ultima’s world class team for specialist anglers who want that edge on difficult 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 stiffness for precision presentation in specific conditions when every bite is critical. With its very high knot strength and superb abrasion resistance.