Black & Decker 20V MAX 12 in. 2-Speed String Trimmer/Edger

What it is and who it’s for

Black & Decker’s 20V Max trimmer is a light, easygoing yard tool designed for homeowners who want the convenience of cordless without chasing commercial-grade power. It’s a 12-inch, single-line trimmer that converts into a wheeled edger, with a two-speed switch to trade runtime for torque. At roughly 7.6–7.9 pounds with a battery, it’s approachable for most users, including those who find gas units too heavy or fussy. If your priorities are simple maintenance, straightforward controls, and a tidy finish around beds, fences, and sidewalks, it fits the brief.

If you’re regularly mowing down thick brush or knee-high weeds, this isn’t the right class of tool. But for typical suburban trimming and weekly edging, it holds its own and keeps yard work pleasantly low-drama.

Setup and ergonomics

Assembly is minimal: click together the shaft, attach the guard, and slide on a charged 20V battery. The telescoping shaft and pivoting front handle offer enough adjustment to find a comfortable stance whether you’re 5'4" or 6'2". I particularly like the soft grip and the overall balance; most of the weight sits near the handle, which makes it easier to guide along fences and around trees without feeling wrist fatigue.

One nit: the foregrip angle clamp on mine needed a firm snug-down. If you set it lightly, it can rotate a notch mid-session, which is annoying. Tighten it positively and it stays put.

Power and cutting performance

This trimmer’s two-speed control is the right feature for a modest battery platform. Low speed is quiet and efficient—perfect for weekly grass whiskers, around stepping stones, and along siding. High speed wakes up the tool for slightly thicker growth, with the POWERDRIVE transmission helping maintain head speed when you push into denser patches.

In practice, I used low for the bulk of routine trimming and toggled to high when I hit longer grass behind the shed or thicker stems along the fence line. It’s not a brushcutter, but staying on top of vegetation keeps you off the back foot. The 12-inch cutting swath and single-line head mean clean results, though you may take an extra pass in heavy spots compared to a dual-line head. The upside: single-line spools are easier to manage and rethread.

Vibration is modest, and the motor sound is more of a hum than a whine. Compared to gas, it’s night-and-day more pleasant to use—no fumes, less racket, and instant start.

Edging mode

Flip the head and you’re in edger mode; a small guide wheel helps keep a straight line along sidewalks and driveway seams. On established edges, the tool does a tidy job, leaving a crisp channel without scattering too much debris. The wheel is a helpful reference but it’s still a string edger—let the line do the work and keep the wheel gliding rather than leaning on it.

A practical note: the guide wheel is plastic. Treat it as a guide, not a curb roller. If you bang it into concrete or slam it down into uneven soil, you’ll shorten its life. Used sensibly, it holds up fine and makes weekend edging almost automatic.

Line feed and spool management

One of the strengths here is the Automatic Feed Spool. It advances line as needed without bumping. During my use, the feed was consistent: no bird’s nests, no random dumps of line, and no fiddling mid-job. I could transition between trimming and edging without pausing to tweak the head.

Line consumption is what you’d expect from a light-duty, single-line head. Routine trimming on low speed sips line; edging and high-speed cutting use more. Replacing the spool is quick, and if you like to respool yourself, the process is straightforward compared to dual-line designs.

Battery, runtime, and charging

Runtime is directly tied to the battery capacity and your speed setting. With a 2.5Ah pack, I typically see about 45–60 minutes of light trimming in low and roughly 20–30 minutes when leaning on high for thick patches or extended edging. That’s enough to make a full lap on a modest yard without swapping packs. If you’re tackling overgrowth, have a second battery ready.

Black & Decker’s 20V Max battery is interchangeable with its broader lineup, which is handy if you already own other tools. Stepping up to a higher-capacity pack meaningfully extends runtime over the smallest batteries—on the order of roughly two-thirds more in my experience—so consider the larger pack if you have more than a small suburban lot.

The included wall-mount charging base (in the kit version) is tidy for storage. Charge speed is serviceable rather than fast; plan on charging between sessions rather than relying on a quick top-up mid-job.

Build quality and maintenance

Construction is largely plastic, which keeps weight down and costs reasonable. The shaft lock, head rotation detents, and spool cover all feel secure when clicked home. As noted, make sure the handle clamp is firmly tightened to avoid drift. Keep the guard clear of wrapped grass and rinse dust off the vents after use to promote airflow and motor longevity.

Spools are widely available, and the line diameter is typical for light-duty consumer trimmers. You can either snap in prewound spools or rewind your own to save a few dollars—one of the benefits of a single-line head.

The tool includes a 2-year limited warranty. I haven’t had to use it, but it’s an appropriate level of coverage for a homeowner trimmer in this class.

Usability notes and tips

• Default to low speed. It’s quieter, easier on the battery, and handles most weekly maintenance.
• Reserve high speed for tall or wet grass and denser spots.
• In edger mode, guide the wheel lightly. Let string speed, not pressure, create the edge.
• Keep an eye on the spool toward the end of the season. Running it all the way down sometimes leads to short line and extra feeding when you start a session.
• If you have a larger property, budget for a second pack. It’s the simplest way to extend runtime without rushing your work.

What I’d change

• The front handle clamp could be a touch more positive. It works, but it’s sensitive to how firmly you tighten it.
• A dual-line option would increase cutting efficiency in tougher grass, though it would complicate spool changes. Given the target user, I understand the single-line choice.
• The charger does the job, but a faster option would be welcome for those with bigger yards or multiple 20V tools.

The bottom line

This 20V trimmer is a well-judged homeowner tool: lightweight, quiet, easy to handle, and simple to maintain. The two-speed control and automatic line feed remove much of the friction that makes yard tasks frustrating, and the wheeled edger mode is genuinely useful for keeping sidewalks and driveway seams sharp. It won’t replace a gas unit for heavy brush, but that’s not its mission.

Recommendation: I recommend it for small to medium yards where routine trimming and clean edging are the primary jobs. It’s especially good for users who value low weight, straightforward controls, and minimal maintenance. If you regularly encounter thick, woody growth or want to blast through overgrown areas in one pass, you’ll outgrow this platform; look to a higher-voltage or dual-line model. For everyone else, this 20V option hits a practical sweet spot of features, comfort, and price.