GICOOL 1-Pack 21" Lawn Mower Blade, Compatible with Greenworks 21" Deck Mower, Replaces Models MO40L03, MO48L4422, MO40L4413

What It Is

The GICOOL 1-Pack 21" Lawn Mower Blade is a direct replacement blade designed for Greenworks 21-inch deck mowers. It’s intended for residential mulching or bagging use, providing a sharp cutting edge for standard grass maintenance.

Fitment & Compatibility

Before buying, verify three things:

• Deck size: Must be exactly 21 inches (measure edge to edge, not the cutting swath).
• Model compatibility: Confirmed for Greenworks models MO40L03, MO48L4422, and MO40L4413. Check your mower’s model number (under the seat or on the frame).
• Blade measurements: This blade is 21" long with a 5-point star center hole (common for Greenworks). Measure your old blade’s length, center hole shape, and thickness (0.15" typical) to ensure a match.
• OEM vs aftermarket: This is a non-OEM replacement. It fits the listed models, but tolerances may differ slightly from factory blades.

Key Things to Know

• Quality: 4.3/5 stars from 43 reviews—generally positive, but a few report balance issues. Check blade balance before installing to avoid vibration.
• Installation: Easy for DIYers—requires a socket wrench (usually 15/16" or 13/16" bolt) and a block of wood to prevent spinning. Torque to 40–50 ft-lbs.
• Gotcha: The blade may come unsharpened or duller than OEM. Expect to sharpen or replace after a few uses on tough grass.
• Durability: Heat-treated steel, but thin (0.15")—not ideal for rocky or debris-heavy lawns.

Should You Buy It

Buy this if you own a compatible Greenworks 21" model and need an affordable, quick replacement for light residential mowing. Skip it if you want OEM-grade sharpness out of the box or have a rough, debris-filled lawn that demands a thicker blade.