Overall, we found that Rio Fluoroflex Plus offers anglers a good material at a reasonable price for fluorocarbon, but it did run oversize. While 6X measured very close to the standard, 2X measured slightly larger than 1X, and 4X measured about 3.5X. Even running larger than other fluorocarbon materials tested, its knot strength was far weaker than the double structure fluorocarbons. One advantage that hard-core anglers and guides appreciate is the fact that it is available in 100 meter guide spools that incorporate a well-marked spool tether, making it easy to distinguish the spool’s size.