Hareline UTC Ultra Thread 70 Denier, Black, 100 Yards

As an Amazon Associate First Cast Fishing earns a commission when you buy through links on this site, at no extra cost to you.

Item weight: 0.1 Ounces

Quick take

A smooth, strong 70 denier nylon fly tying thread that is forgiving for beginning fly tiers.

This 70 denier fly tying thread is a flat, smooth, lightly waxed nylon that builds bulk slowly. It comes on a 100-yard spool and is rated to about 2 pounds of breaking strength. The low-profile wraps suit small trout flies, and the moderate strength gives newer tiers room to learn thread tension.

Best for

Tying size 6 to 16 trout flies
Fly tiers new to the craft
Building nymphs and wet flies

Skip if

You need a very fine thread for small saltwater flies
You prefer pre-waxed or un-waxed specialty thread

Strengths

2 lb breaking strength prevents thread from breaking as you learn proper tension
Lightly waxed coating prevents splitting and helps it grip itself
Flat, smooth thread lays flat on the hook for clean, even wraps

Trade-offs

70 denier is thicker than modern specialty threads; bulk flies look less delicate
Limited color range compared to specialty fly tying thread brands
General-purpose thread; not optimized for tiny flies or unusual colors

Fishing fit

Techniques: Fly fishing
Skill level: Beginner

Specifications

Specifications
Type	fly tying thread
Denier	70
Length	100 yards
Breaking strength	2 lb
Color	Black

Updated 21 October 2026