Get your flies just below the surface with the Scientific Anglers Frequency Intermediate Fly Line — a versatile slow-sinking line built for controlled subsurface presentations. Ideal when you need to fish streamers, wet flies, or nymphs just under surface chop without sinking too deep, this intermediate line delivers smooth casting and excellent control in stillwater and mild river situations.

Why this line performs:

• Slow intermediate sink rate: At about 1.25 inches per second, it pulls flies under the surface gently — perfect for mid-depth fishing where fish hold.
• Smooth casting: Thin diameter cuts through wind, improving shootability and accuracy.
• Balanced taper: Offers good load and control for a range of rod actions and casting styles.
• All-purpose versatility: Works great for stillwater lakes, dams, and calmer river pools where subtle presentation is key. We use the heavier weights on the Breede river with good success.
• Suitable for many species: Trout, bass and saltwater species

Features & benefits:

• Slow sink rate (~1.25 ips) for controlled subsurface fly placement.
• Thin diameter improves distance and wind penetration.
• Mid-length head enhances line control.
• Braided multifilament core (clear or Atmosphere Blue variants).

Choose from WF-5I to WF-8I weights to match your rod and target fishery for everything from light trout work to bigger stillwater streamers.