Cordless Weed String-Trimmers/Lawn Mower, 21V 3-in-1 with 8 Replace Auto Line Feed, Electric Grass Trimmer for Garden, Lawn, 120 Mins of Non-Stop Review

Overview

This isn’t a full lawn mower—it’s a 21V cordless string trimmer and edger combo that also functions as a mini mower for small, tight spaces. The “Weed” brand 3-in-1 tool is designed for homeowners with modest yards (under ¼ acre) who want a lightweight, battery-powered solution for trimming around fences, garden beds, and walkways, plus light mowing on tiny patches of grass. At $69.99, it’s a budget-friendly entry point for cordless lawn care, but you’re trading runtime and power for that price.

Who Should Buy This

• Apartment or townhome dwellers with small lawns – If you’ve got a postage-stamp yard or a strip of grass in front of a condo, this trimmer’s 120-minute runtime and 8-foot reach can handle it without dragging out a gas trimmer or extension cord.
• Homeowners who hate gas cans and pull cords – If you dread mixing fuel or wrestling with a stubborn starter rope, this electric trimmer starts instantly with a trigger. No fumes, no noise complaints from neighbors.
• Gardeners needing precision edging – The 3-in-1 design (trimmer, edger, mini mower) lets you switch to edging mode for clean lines along sidewalks without buying a separate tool.
• Budget-conscious buyers on a strict limit – At $69.99, this is one of the cheapest cordless trimmers with an automatic feed system. If you’re not ready to spend $150+ on a premium model, this is a reasonable starter.

Key Features Breakdown

• 21V Battery & 120-Minute Runtime – The battery is small (2.0Ah typical), so that “120 minutes of non-stop” runtime is optimistic. In real-world use with thick grass, you’ll get 30–45 minutes of continuous trimming. It’s enough for a small yard but not a half-acre lot. The battery charges in about 2–3 hours.
• 8 Replaceable Auto Line Feed – You get 8 pre-cut line spools included. The auto-feed mechanism bumps the line forward when you tap the head on the ground, but it’s not as reliable as a bump-feed on higher-end trimmers. Expect occasional jams or overfeeding.
• 3-in-1 Design – The head rotates 90 degrees for edging, and the included wheeled kit converts it into a small mower. The mower function works only on very short, thin grass—think moss or newly seeded patches. Don’t expect it to replace a real mower.
• Automatic Line Feed – Unlike manual-feed trimmers where you stop to adjust line, this one feeds automatically when you press the head. It’s convenient but can waste line if you’re aggressive with the tapping.
• Lightweight Build – At around 5 pounds, you can use it one-handed for hours without fatigue. The telescoping shaft adjusts for different user heights (5’ to 6’2").

Pros

1. Extremely lightweight – At under 6 pounds, it’s one of the lightest trimmers I’ve tested. Great for seniors or anyone with wrist or shoulder issues.
2. 8 replacement spools included – Most budget trimmers give you 1–2 spools. Having 8 means you won’t need to buy line for months.
3. Quiet operation – At 75 dB, you can trim at 7 AM without waking the neighbors. No earplugs needed.
4. Tool-free head adjustment – Switching from trimming to edging takes 5 seconds—just twist the head lock and rotate.
5. Budget-friendly price – $70 is hard to beat for a cordless trimmer with a battery and charger included. Comparable models from Ryobi or Black+Decker cost $100–$130.
6. Battery indicator light – The handle has a small LED that shows charge level, so you won’t get stranded mid-job.

Cons

1. Short battery life under load – The 120-minute claim is for light trimming on short grass. In thick weeds or wet grass, expect 20–30 minutes. You’ll want a second battery for any yard over 2,000 sq ft.
2. Auto-feed can be finicky – The line sometimes feeds too much (wasting line) or not enough (leaving you cutting with a short nub). You’ll need to manually pull line occasionally.
3. Not for heavy-duty weeds – The 21V motor struggles with thick brush, brambles, or overgrown grass over 6 inches tall. Stick to light maintenance trimming.
4. Mini mower mode is gimmicky – The wheeled mower attachment works only on perfectly flat, short grass. On uneven ground or taller grass, it bogs down and leaves uncut patches.

Bottom Line

The Weed 21V 3-in-1 is a solid choice for small-yard owners who want an affordable, lightweight trimmer for light maintenance—think trimming around flower beds, edging sidewalks, and touching up corners a mower misses. It’s not for heavy-duty weed whacking or large properties. The 8 spools and auto-feed are nice perks, but the battery life and motor power are limiting. If your lawn is under ¼ acre and you’re on a tight budget, this is a good value. For bigger yards or thicker growth, spend more on a 40V or gas model. Recommended for apartment dwellers and budget-conscious gardeners.

Frequently Asked Questions

Q: Can I use this as a full lawn mower for my entire yard? No. The “mower” mode is for tiny patches (under 50 sq ft) of very short, thin grass. It won’t replace a standard push mower. Use it for trimming and edging only.

Q: How long does the battery take to charge? About 2–3 hours from empty. The charger is a standard wall plug, not a rapid charger. If you have a larger yard, buy a second battery to swap while one charges.

Q: Does the auto-feed work reliably? Mostly yes, but you’ll occasionally need to press the head harder on the ground to trigger it. If the line stops feeding, turn the trimmer off, manually pull about 2 inches of line from the spool, and cut off the excess with scissors. This fixes 90% of feed issues.