Weed Warrior Autowinder II Universal Fit String Trimmer Replacement Bump Head

What It Is

The Weed Warrior Autowinder II is a universal replacement bump head for gas and electric string trimmers. It automatically feeds trimmer line when you tap the head on the ground, saving you from manual rewinding. Designed for residential trimming, edging, and light commercial use.

Fitment & Compatibility

Before buying, check these three things:

• Shaft size & thread type: The Autowinder II fits most straight and curved shaft trimmers with a 10mm (M10 x 1.25) or 7/16″-20 UNF (20 threads per inch) shaft thread. If your trimmer has a metric 10mm x 1.25 left-hand thread (common on Echo, Shindaiwa, some Ryobi), you’ll need the included adapter. For 7/16″-20 UNF (common on Stihl, Husqvarna, Craftsman, Toro), use the other adapter.
• Line capacity: Accepts 0.080″ to 0.105″ diameter line. Do not use thicker line—it will jam or break the head. Standard 0.095″ works best.
• Brand/model notes: Universal fit, but not compatible with trimmers that use a proprietary head (e.g., some DeWalt 20V, older Weed Eater featherlite, or battery models with a fixed head design). If your trimmer has a curved shaft with a plastic head that snaps on, this won’t work.

What to measure: Remove your current head. Measure the shaft diameter (should be 10mm or 7/16″) and count the threads per inch if unsure. Check your owner’s manual for shaft thread size.

Key Things to Know

• Installation difficulty: Easy—takes 5-10 minutes. No tools required beyond the included wrench. Line loading is straightforward: push line through the eyelets, wind manually, then snap the spool in.
• Quality: Mixed reviews. Many users report reliable auto-feed, but some say the spool can break after a few uses if you hit hard objects. The plastic housing is lighter than OEM metal heads—expect shorter lifespan if you trim near fences or rocks.
• Common gotcha: The “autowinder” mechanism can jam if you use line thicker than 0.105″ or if you overfill the spool. Stick to 0.095″ line and leave 6″ of line exposed after winding. Also, the bump knob may wear out faster than name-brand heads—buy a spare if you trim frequently.
• Line loading: You must manually wind the line onto the spool (not a “speed spool”). This is slower than some newer heads but still faster than replacing a fixed head.

Should You Buy It

Buy this if you have a standard gas trimmer (Echo, Stihl, Husqvarna, Ryobi) and want a cheap, universal replacement that works without needing a specific brand. Skip it if you use a battery trimmer with a proprietary head, need heavy-duty commercial durability, or prefer a speed-load head that winds line in seconds. For the price, it’s a solid budget option for occasional to moderate use.