Not, Really a fly line at all this line is designed to have as little drag on the water as possible and slip through the guides with ease. I cut mine in half so I can add it to my normal fly line like a tip. That way if you want to fish an indo, or the hatch starts popping off you can remove the line and re rig with max efficiency. You get 2 lines for the price of one this way too!
RIO's updated Euro Nymph line has been thoroughly vetted and approved by FIPS Mouche as "Competition Legal". A system of special marks on the line has been endorsed and approved by FIPS Mouche, ensuring that competitive anglers do not have to waste valuable fishing time by having their line checked during competition hours.