IQ is fluorocarbon which refracts light in almost the same way as water making it almost invisible when immersed. It is stiffer than normal nylon so improving anti-tangle and anti-eject properties.
Team Korda have extensively field tested all breaking strains and were so impressed they were compelled to add it to the already impressive range. 10lb is ideal for finely tuned open water situations. 15Ib is a superb all rounder and 25lbs forms an impressive Stiff link