What it is
Hareline Lead Free Round Wire is a lead-free metal wire in a round profile you wrap on the hook to add weight. It’s not as heavy as traditional lead, but it’s durable and tarnish resistant. On the hook it builds smooth, even underbodies and helps get flies down into a deeper part of the water column.
What to tie with it
Use it for weighting fly patterns by wrapping the hook shank before you tie the body, or by tying in weight strips. It’s a go-to move for adding controlled weight to nymphs, wet flies, and articulated streamers without changing the fly’s silhouette much. Because it’s round, you can lay down tight, consistent wraps and then cover it cleanly with thread, dubbing, or chenille.
Flies and the fish they're for
This wire is the standard kind of material you see called for in lots of nymphs, wet flies, and streamers where you need the fly to sink, even when the recipe just says “lead wire” generically. Weighted nymphs tied this way are fished for trout in rivers and tailwaters when you need to get into the strike zone. Weighted streamers and articulated streamers are commonly fished for smallmouth and trout in moving water, and also see plenty of use for stripers where getting the fly down matters.
How it compares
Compared with traditional lead wire (including Danville Spooled Lead Wire), lead-free wire is lighter and more environmentally safe, and it resists tarnish better, but you give up some sink rate. If you need more weight than the wire provides, you can lean on non-wire options like beads, cones, or dumbbell eyes, or combine the wire with a heavier bead or cone to make up the difference.