Using pre-wound replacement spools can make restringing quick and tidy. Many 40V models on this page use dual-line heads with either 0.065 in (about 20 ft) or 0.080 in (about 17 ft) line. Steps can vary, but this general approach may help:

1. Power off and remove the battery.
2. Check your line size. Match the spool diameter and length listed for your tool.
3. Remove the spool cap. Most caps release with side tabs; avoid force if it resists.
4. Swap the empty spool for a pre-wound one. Seat it so the two lines feed through the eyelets.
5. Leave a few inches of line out on both sides, then reinstall the cap.
6. Advance line per your head type. Auto-feed may advance on power cycling; bump-feed advances by tapping.

For exact instructions, refer to your manual, as mechanisms differ by model.

Head designs vary, so it’s a good idea to start with the simplest approach and consult your manual for model-specific details.

• If you only need the spool out: Power off and remove the battery. Most heads use a removable spool cap. Clear debris, press the cap tabs, and lift the cap and spool straight off. This is often all that’s needed for line replacement.
• If you need the entire head off: Some heads are retained by a center fastener or threaded collar. Thread direction can vary, so look for arrows or markings. Hold the shaft steady to avoid damage and keep parts organized.

Cap-and-spool kits offered here can be a convenient alternative if the cap is worn or difficult to remove.

“Brushless” describes the motor; the line-loading method depends on the head type, not the motor. Products on this page support two common systems:

• Auto-feed, dual-line: Typically uses pre-wound spools (often around 0.065 in, ~20 ft). Power off, remove the cap, swap in the replacement spool, feed both lines through the eyelets, and reinstall the cap. Line advances automatically per the tool’s design.
• Bump-feed, dual-line: Often uses heavier line (commonly around 0.080 in, ~17 ft). Load a compatible pre-wound spool into the head, or follow your manual’s winding arrows if using bulk line. Tap the head on the ground as directed to advance line.

Always match the spool’s line size and length to your model’s specs to help prevent jams or premature wear.

Auto-feed systems are designed to advance small increments of line without manual bumping. On many dual-line heads featured here, the mechanism feeds line when certain conditions are met—such as cycling the trigger, starting the motor, or when the line shortens during use.

• Benefits: More consistent cutting length and fewer interruptions.
• What it needs: The correct spool type and line size (e.g., commonly 0.065 in or 0.080 in) to function smoothly.
• Care tips: Keep the eyelets and cap clean, replace worn caps, and use compatible pre-wound spools to reduce tangles.

If line isn’t advancing, inspect the spool for crossed wraps, confirm you’re using the specified diameter, and review your manual for the exact feeding trigger your model uses.

The right choice depends on your trimmer head and the manufacturer’s specs. The spools on this page highlight two common options for 40V dual-line heads:

• Approx. 0.065 in line, ~20 ft: Often used on lighter-duty, auto-feed heads.
• Approx. 0.080 in line, ~17 ft: Common on heavier-duty, bump-feed heads.

How to pick: Check your tool’s label or manual for line diameter, confirm dual-line compatibility, and match your model number to the compatibility list on each product page. If your cap is worn, consider a spool-and-cap kit. Choosing pre-wound spools can simplify reloading and help reduce tangles. Pickup or delivery options may be available to get you back to trimming sooner.