Semperfli Wire is non tarnishing, which means it can be used in saltwater. 

Having been developed and manufactured in semperflies own computerized spooling machinery, the wire is put onto the spool with touching turns in totally level traverse, why is this important? Because you will not get a birds nest when tying flies or have wires trapped. The spools have a removeable cap to re-trap the wire once you have removed a section to tie your flies.

Tie on Wire and tie off with thread. Rather than cutting simply wiggle and it will break saving damage to your scissors

There are 6m / 6.5 yards (approx ) per spool.