Best Greenworks 40V 12 in String Trimmer
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If you are looking for the best Greenworks 40V 12 in string trimmer, this listing is a combo kit: a 12-inch cordless string trimmer and a 390 CFM leaf blower on one 40V battery platform. The listing and the Greenworks product page agree on the battery, the 3-year warranty and the blower’s 110 MPH and 390 CFM rating. They disagree on runtime and weight, and this page reports both figures rather than choosing one. This review covers that one kit.
Quick answer
- Pick it if you want a 12-inch battery trimmer and a blower on one 40V battery, and a combo kit suits your yard work.
- The Greenworks page says the kit includes a 2.0 Ah battery and a charger. The listing states the battery but does not mention a charger.
- The runtime figures disagree: the listing gives an average battery life of 2 hours, and the Greenworks page says up to 30 minutes of runtime.
- Skip it if you want the trimmer alone, or if you need a weight you can rely on, because the listing gives two different weights.
The product at a glance
The table separates what the Amazon listing says from what the Greenworks page says. Cells read “not stated” where a source is silent. Nothing here comes from memory or from retail review text.
| Item | Amazon listing says | Greenworks page says |
|---|---|---|
| Product | Greenworks 40V 12 in string trimmer and 390 CFM blower combo | 40V 12-inch cordless string trimmer and 390 CFM leaf blower combo kit |
| Model | STBA40B210 | STBA40B210 |
| Battery | One lithium-ion battery, included; 2.0Ah | Includes 40V 2.0 Ah battery |
| Charger | not stated | Includes battery charger |
| Charge time | 60-minute charge (bullet) | not stated |
| Runtime | Battery average life 2 hours (condition not stated) | Up to 30 minutes of runtime |
| Cutting width | 12 inches | 12-inch cutting path |
| Line and feed | .065-inch auto-feed | .065-inch dual line auto feed head |
| Blower | 390 CFM; 110 MPH (bullet) | 390 CFM; 110 MPH |
| Speed | 7500 rpm | not stated |
| Weight | 16.5 pounds (specification field); 8 LB design (bullet) | not stated |
| Dimensions | 64.5 in L x 7.5 in W | not stated |
| Warranty | 3 Year (manufacturer warranty description) | 3 year tool / battery warranty |
| Speed control | not stated | Variable speed trigger with cruise control (blower) |
| Yard size | not stated | Perfect for yards up to 1/3 acre |
Across the table, the two sources agree on the model, the 12-inch cut, the .065-inch auto feed, the 390 CFM and 110 MPH blower rating, the 2.0 Ah battery and the 3-year warranty. They disagree on runtime and weight, and only the Greenworks page states the charger and the yard size. Those are the points to check before you order.
One calculation uses only stated values. The listing gives a 40 V, 2.0 Ah battery, so volts times amp-hours gives 40 V x 2.0 Ah = 80 Wh. This is our arithmetic and it is the energy in the pack, not a runtime. The two runtime figures in the sources cannot be turned into a cutting estimate from this page, because they disagree and the listing gives no condition for its figure.
The runtime gap is the largest disagreement. The listing says “Battery Average Life: 2 hours” with no load or cutting condition. The Greenworks page says “Up to 30 minutes of runtime” and describes the kit for “yards up to 1/3 acre.” The listing does not say whether its 2-hour figure refers to one charge, and the Greenworks page does not explain the gap. This page reports both figures and does not pick one.
The weight is also inconsistent inside the listing. Its specification field reads “Item Weight: 16.5 pounds,” while a bullet describes an “8LB balanced design.” The Greenworks page gives no weight. The listing does not say which figure covers the whole kit, so this page does not choose between them.
The listing’s bullets also describe a 12-inch trimmer with a .065-inch auto-feed, a 110 MPH blower with cruise control, and a 2.0Ah battery with a 60-minute charge. The Greenworks page confirms the 110 MPH and 390 CFM blower rating and the .065-inch auto feed head. It describes the speed control as a variable speed trigger with cruise control, which it attaches to the blower.
Who it suits
This kit suits a homeowner who wants a 12-inch battery trimmer and a blower on one 40V battery, for edges, beds and leaves in a yard within the size the Greenworks page names. The page says the kit is “Perfect for yards up to 1/3 acre.” A yard of that size and a regular mix of trimming and blowing is the job the kit is built around.
It also fits a buyer who is already in the Greenworks 40V system. The Greenworks page says “The Greenworks 40V lithium-ion platform powers 75+ outdoor products,” so a battery bought now can run other tools later. If you are comparing trimmer families before you choose, our page on Greenworks and EGO Power+ string trimmers compared lays out the two platforms side by side.
If you want a 40V Greenworks mower in the same system, our Greenworks 40V electric lawn mower page covers that tool type, so you can see how the battery fits a different job.
Buyers who already own a Greenworks 40V blower may not need the one in this kit. The listing does not say whether the blower can be bought without the trimmer, so check the kit contents before you order.
Skip it if
- You want the trimmer alone. This is a kit, and the Greenworks page lists a blower, a battery and a charger along with the trimmer.
- You need a runtime you can rely on. The two sources disagree, and neither gives a condition that would let you check the figure.
- You need a weight you can rely on. The listing gives 16.5 pounds in one field and an 8 LB design in a bullet.
- Your yard is larger than the page’s stated size. The Greenworks page says the kit is “Perfect for yards up to 1/3 acre,” and it does not describe a larger yard.
- You plan to run the trimmer without its guard. The Greenworks page says “No, string trimmers should never be operated without a guard.”
What the listing does not say
The listing does not mention a charger. The Greenworks page says the kit “Includes 40V 2.0 Ah battery and charger,” so the charger is confirmed only by the manufacturer page. Before you buy, confirm that the charger is in the box you receive.
The listing’s bullets make comparison claims, such as clearing edges “in half the time” and a unit that is “30% lighter than gas alternatives.” The listing gives no basis for either, so this page does not repeat them. The item highlight also calls the kit “Lightweight,” and the weight figures above show that the listing does not support one number for that word.
The Greenworks page explains the auto-feed mechanism in its FAQ: “Auto-feed string trimmers use centrifugal force to release trimmer line.” The listing does not explain it. The Greenworks page also describes a guard that reduces debris flung toward the user, which the listing does not mention.
The Virginia Tech guide says “String trimmers are known to throw stones, sticks, and other objects at high speeds.” It advises: “Secure long hair above the shoulder while operating a string trimmer.” It also notes that battery trimmers depend on the battery, and says “Lithiumion batteries are recommended for extending the run time of battery-operated trimmers.” That is general guidance for trimmers, not a claim about this kit.
The listing gives 64.5 inches by 7.5 inches as its item dimensions. Our reading is that these are packed dimensions, but the listing does not say so, and the Greenworks page gives no dimensions. Check the space the kit needs for storage rather than relying on the listing field.
How we chose
This post covers one product: ASIN B01CA4PS8C, the Greenworks 40V 12 in String Trimmer and 390 CFM Blower Combo with a 2.0 Ah battery, model STBA40B210. It is a single-product review in this batch, so the page does not rank it against other trimmers or kits.
The product data comes from the stored Amazon scan for this ASIN, dated 2026-10-12 (the STORED date). We kept the brand, model, battery, charge, runtime, cut width, weight, dimensions, speed and warranty fields. We left out the bullets that make price or savings claims, and the rating and sales-rank fields.
The public product page on greenworkstools.com refused our request. We used the product page on the agents.greenworkstools.com subdomain instead. It carries the same product title and model number, STBA40B210, and we opened it on 2026-10-22. We did not take any fact from retailer or search-summary pages. Retailer Q&A pages in search results give different runtime estimates, and we did not use them.
For trimmer safety points we opened a Virginia Tech Extension lawn care guide on 2026-10-22. That guide covers powered hand tools in general, so we used only its trimmer lines.
The ASIN is a trimmer-led combo, and the keyword asks for the trimmer. We therefore treat the blower as part of the purchase rather than a separate product, and we do not split the kit into two products. Every figure on this page is for the kit as the listing and the Greenworks page describe it.
What we could not verify
- The runtime. The listing says 2 hours of average battery life with no condition, and the Greenworks page says up to 30 minutes. We could not check either figure.
- The weight of the whole kit. The listing gives two figures, and the Greenworks page gives none.
- The 60-minute charge in the listing. The Greenworks page does not state a charge time, so we did not confirm it.
- The 7500 rpm speed in the listing. The Greenworks page does not state a speed for the trimmer.
- Whether the 2.0 Ah battery is the same one sold with other Greenworks 40V tools. The Greenworks page says the 40V platform powers 75+ outdoor products, but it does not describe this battery’s compatibility with a specific tool.
- Stock, current pricing and any service notice for this kit. This page gives no prices, and we did not check stock.
FAQ
Does the kit include a charger?
The Greenworks page says the kit “Includes 40V 2.0 Ah battery and charger.” The Amazon listing states the battery but does not mention a charger, so confirm the charger in the box you receive.
How long does the battery last?
The sources disagree. The listing gives an average battery life of 2 hours with no condition stated. The Greenworks page says up to 30 minutes of runtime. This page cannot tell you which figure applies to your work.
How much does the kit weigh?
The listing gives two figures: 16.5 pounds in its specification field, and an 8 LB design in a bullet. The Greenworks page gives no weight. If the weight matters to your purchase, check it with the seller before you buy.
Does the trimmer have an auto-feed head?
Yes. The listing describes a .065-inch auto-feed, and the Greenworks page describes a .065-inch dual line auto feed head. The page explains that each time the unit is activated, the spinning head releases line, and that a spring-loaded mechanism relocks the line after a short length has been released.
Can I run the trimmer without the guard?
No. The Greenworks page says string trimmers should never be run without a guard. It explains that the guard reduces debris flung toward the user and also keeps the line from overextending.
What is the warranty?
Both sources say 3 years. The Greenworks page describes a 3 year tool and battery warranty, and the listing gives 3 Year as the manufacturer warranty description.
Bottom line
Buy this kit only if a combined trimmer and blower on one 40V battery is what you want, and you can accept runtime and weight figures that the two sources do not agree on. If a verified runtime or weight matters to the purchase, get both from the seller in writing before you order.
Sources
- Amazon.com listing for ASIN B01CA4PS8C, stored scan (opened 2026-10-12): https://www.amazon.com/dp/B01CA4PS8C
- Greenworks Tools, “40V 12-Inch Cordless String Trimmer And 390 Cfm Leaf Blower Combo Kit,” product page, model STBA40B210 (opened 2026-10-22): https://agents.greenworkstools.com/products/40v-12-string-trimmer-and-390-cfm-leaf-blower-combo
- Virginia Tech Extension, “Powered Hand Tools Safety: Lawn Care Training Guide,” publication BSE-50 (opened 2026-10-22): https://pubs.ext.vt.edu/BSE/BSE-50/BSE-50.html
