Updated September 16, 2026. Disclosure: As an Amazon Associate, we earn from qualifying purchases.
Quick answer: The Greenworks STF457 sits between light-duty homeowner trimmers and premium high-voltage models. It combines a 16-inch cut, brushless top-mounted motor, 0.080-inch dual line, and an attachment-capable shaft. The main caution is weight: Greenworks lists 9.7 pounds before the battery is installed.
Our verdict: Best for homeowners who want one 40V power head for trimming plus compatible attachments. It offers more versatility than the EGO or BLACK+DECKER models, but it is the heaviest bare tool in this group and uses a conventional bump-feed head.
Check availability at Greenworks →
Research note: This is a research-based review. We have not personally tested this string trimmer. We reviewed current manufacturer specifications, the owner manual where available, warranty terms, kit contents, battery compatibility, and current owner-feedback patterns.
Compare this model with the other picks in our best cordless string trimmers guide, or browse the electric string trimmer hub.
Greenworks STF457 specifications
| Battery platform | Greenworks 40V |
|---|---|
| Cutting path | 16 inches |
| Line | Dual 0.080-inch spiral-twist line |
| Line feed | LOAD N’ GO bump feed |
| Motor | Brushless, top mounted |
| Speed control | Variable trigger |
| Attachment capable | Yes; Greenworks lists compatibility with several common attachment systems |
| Bare-tool weight | 9.7 lb without battery |
| Included kit | 4.0Ah battery and charger |
| Manufacturer runtime | Up to 50 minutes |
| Listed charge time | 120 minutes |
| Warranty | 3 years for tool and battery |
Best for
- Greenworks 40V battery owners.
- Homeowners who want to add an edger, pole saw, cultivator, or other compatible attachment.
- Medium-size yards that benefit from a 16-inch swath.
- Buyers who prefer a conventional bump-feed head.
Consider another model if
- Users who prioritize low working weight.
- Small yards where a compact trimmer-edger is enough.
- Anyone who wants automatic line feed or push-button winding.
- Greenworks 60V owners; Greenworks battery voltages are separate platforms.
The attachment system is the reason to choose it
The split-shaft design accepts compatible attachments, so the same motor and battery can power more than the string-trimmer head. Greenworks specifically names compatibility with attachments from Greenworks, Ryobi, TrimmerPlus, Yardworks, and others, but attachment fit can vary by generation and coupler. Confirm the exact attachment before buying. This flexibility adds joints and weight that a fixed-shaft trimmer does not need.
Cutting setup
A brushless top-mounted motor drives a 16-inch path with dual 0.080-inch line. That line is heavier than the BLACK+DECKER’s 0.065-inch line but lighter than the 0.095-inch line supplied with the EGO and RYOBI. The variable trigger helps reduce speed near bark, fences, and beds. Line advances through a bump-feed head, which is simple and familiar but requires contact with the ground.
Runtime and charging
Greenworks claims up to 50 minutes with the included 4.0Ah battery and lists a 120-minute recharge time. Both numbers are manufacturer benchmarks. Dense grass, high trigger use, attachments, temperature, and battery condition change actual results. A second 40V pack can reduce downtime and can also power more than 75 products in Greenworks’ current 40V range.
Weight deserves attention
Greenworks lists 9.7 pounds without the battery. The top-mounted motor can improve balance relative to a heavy motor at the cutting head, but the total tool is still substantial once the 4.0Ah pack is installed. Buyers with shoulder, wrist, or back limitations should handle a comparable setup before ordering or plan to use the included shoulder strap if supplied with the selected kit.
Pros and cons
Pros
- Attachment-capable shaft
- 16-inch cutting path
- Brushless top-mounted motor
- Variable-speed trigger
- Complete 4.0Ah kit
- Broad Greenworks 40V tool platform
Cons
- 9.7-pound bare-tool weight
- Battery makes working weight higher
- Conventional bump feed
- Only 0.080-inch line
- Attachment compatibility still needs model-by-model confirmation
Final recommendation
Best for homeowners who want one 40V power head for trimming plus compatible attachments. It offers more versatility than the EGO or BLACK+DECKER models, but it is the heaviest bare tool in this group and uses a conventional bump-feed head.
Frequently asked questions
Does the STF457 include a battery?
The reviewed kit includes one 4.0Ah Greenworks 40V battery and a charger.
What line does it use?
Greenworks specifies dual 0.080-inch spiral-twist line.
Which attachments fit?
Greenworks says the power head accepts attachments from several common systems, including Greenworks, Ryobi, TrimmerPlus, and Yardworks. Confirm the exact coupler and attachment model before purchasing.
How long does the battery last?
Greenworks advertises up to 50 minutes with the included pack. Actual runtime depends on vegetation, trigger use, temperature, and attachment.
Can a Greenworks 60V battery be used?
No. Greenworks 40V and 60V batteries belong to different platforms and are not interchangeable.
Sources and review method
Specifications and package details can change. Match the exact model number and included-items list before ordering. Manufacturer runtime and noise figures are conditional claims, not guarantees.
Read our affiliate disclosure and learn more about our research process.