84005221 21"Lawn Mower Blade Replacement for Murray/Blackmax/Daye/Hyper Tough MNA152901 MNA152903 MNA152701 Push Mower Blade, Lawn Dethatcher Blade 2105200317/2105200317A

What It Is

This is a 21-inch replacement blade compatible with Murray, Blackmax, Daye, and Hyper Tough push mowers. It works as a standard cutting blade or a dethatcher blade (depending on model) and fits mower models MNA152901, MNA152903, and MNA152701.

Fitment & Compatibility

Before buying, check these points:

• Deck size: Your mower must have a 21-inch cutting deck. This blade is not for 20-inch or 22-inch decks.
• Center hole: Measures 7/8 inch diameter. Verify your mower’s spindle matches.
• OEM numbers: Replaces Murray/MTD part 84005221 and also 2105200317/2105200317A (used on some Hyper Tough models).
• Blade type: This is a straight/standard blade, not a mulching or high-lift blade. If your mower requires a specific blade shape (e.g., curved or with air lifts), this won’t fit.
• Confirm your model: Double-check your mower’s model number (stamped on the deck or under the seat) against the listed compatible models. Not all Murray 21-inch mowers use this blade.

Key Things to Know

• Quality: Made of steel with a painted finish. Expect decent durability for residential use, but may dull faster than premium OEM blades on heavy or rocky lawns.
• Installation: Straightforward – remove the old blade, install this one with the correct orientation (cutting edge facing up toward the deck). Use a torque wrench to tighten the center bolt to 30-50 ft-lbs.
• Sharpening: Can be sharpened, but the paint coating may chip. If you sharpen, rebalance the blade afterward.
• Dethatcher use: Some versions of this blade are sold as a dethatcher. Check the product description – if you need a true dethatcher (with tines or teeth), this may not be it. This is primarily a cutting blade.

Should You Buy It

Buy this if you need a direct replacement for a Murray, Blackmax, Daye, or Hyper Tough 21-inch push mower and want a budget-friendly option that fits common OEM numbers. Skip it if you need a mulching or high-lift blade, or if your mower requires a specific OEM-only design. For the price, it’s a solid value for standard residential cutting.