Milwaukee M18 FUEL String Trimmer — Which Line and Head Fits?

Milwaukee’s M18 FUEL outdoor power equipment lineup has expanded quickly, and the string trimmers are among the most popular cordless options for homeowners and professionals who are already invested in the M18 battery platform. But when the trimmer line wears out — and it always does — knowing exactly which line diameter, head type, and spool fits your model saves time and frustration.

Here is what you need to know about replacement line and heads for Milwaukee M18 string trimmers and the M18 FUEL Brush Cutter.

M18 trimmer models and their line specs

Milwaukee currently offers several M18 string trimmer configurations. The key models for parts compatibility:

• M18 FUEL String Trimmer (2725-20) — The original M18 FUEL trimmer. Uses 0.080” line in a bump-feed head.
• M18 Brushless String Trimmer (2828-20E) — A newer brushless model with an EASY LOAD trimmer head. Also uses standard 0.080” line.
• M18 FUEL Brush Cutter — Designed for heavier clearing work. Can accept a blade attachment in addition to a standard trimmer head with 0.080” or 0.095” line.

Across all of these models, 0.080” round trimmer line is the standard specification. This is one of the most common line diameters in the industry, which means you have a wide selection of both OEM Milwaukee line and aftermarket options.

Choosing replacement line

The stock line that ships with Milwaukee M18 trimmers is 0.080” round. You can also run:

• 0.080” twisted or serrated line — Cuts slightly more aggressively than round line and tends to produce a cleaner edge. Fits the stock head without modification.
• 0.095” line — Some users step up to 0.095” for thicker weeds. This works in the Brush Cutter head and some aftermarket heads, but may not feed properly in the stock 2828-20E EASY LOAD head. Check before loading.
• 0.065” line — Thinner than standard. Feeds easily but wears faster and struggles with anything beyond light grass. Not recommended unless you are only maintaining a manicured lawn edge.

For most homeowners, sticking with 0.080” round or twisted line is the best balance of cutting performance, line life, and compatibility with the stock head.

Trimmer head options

Milwaukee’s EASY LOAD head (found on the 2828-20E) is designed for fast line loading without disassembly — you feed the line through a hole in the head and wind it by spinning the head. If this head wears out or the bump mechanism fails, the OEM replacement head is the simplest swap.

Aftermarket bump-feed heads are available for Milwaukee M18 trimmers. When shopping for a replacement:

• Thread size and direction — Verify the arbor thread matches your Milwaukee model. Most use a left-hand thread.
• Line capacity — Ensure the aftermarket head accepts at least 0.080” line and holds enough length for a reasonable working session.
• Balance and weight — Oversized aftermarket heads can change the tool’s balance point, making it more tiring to use over a long session.

The M18 FUEL Brush Cutter also accepts a metal blade attachment for heavy brush clearing. The blade mount is specific to the Brush Cutter — it does not fit the standard M18 string trimmers.

HIGH OUTPUT battery benefits for outdoor tools

All Milwaukee M18 batteries work in all M18 tools — that includes standard M18 packs, M18 HD (High Demand), and M18 HIGH OUTPUT packs. For outdoor power equipment, the HIGH OUTPUT batteries are worth considering:

• M18 HIGH OUTPUT 6.0Ah and 8.0Ah packs deliver higher sustained current than standard packs, which translates to more consistent motor speed under heavy load
• M18 HIGH OUTPUT 12.0Ah provides maximum runtime for extended trimming sessions
• Every M18 battery is backward compatible, so your existing packs still work — HIGH OUTPUT just gives you more headroom

This backward compatibility is a major advantage of the M18 platform. Unlike some brands where different voltage lines have different battery interfaces, Milwaukee keeps everything on one 18V system.

What this means for replacement parts

Milwaukee M18 FUEL trimmers use widely available 0.080” line, making replacements easy to source. The trimmer heads are model-specific, so match your model number before ordering a replacement head assembly.

Browse our catalog for M18-compatible trimmer line, replacement spools, and aftermarket bump-feed heads. Keeping a few spare line refills on hand means you spend more time trimming and less time running to the store.