331737B Mulching Lawn Mower Blade, Compatible with AYP/Craftsman/Hus qvarna/Pou LAN 21" Cut Mowers, Replaces 165833, 175052, 406712, 176135, 532175064, 2 Pack

What It Is

The 331737B is a 21-inch mulching blade set (2-pack) designed to replace OEM blades on AYP, Craftsman, Husqvarna, and Poulan Pro walk-behind mowers with 21" cutting decks. It recirculates clippings for fine mulching, eliminating bagging needs.

Fitment & Compatibility

• Deck size: Only for 21-inch cut mowers. Measure your existing blade length center-to-center (mounting hole to tip) – must be exactly 21 inches.
• OEM cross-references: Replaces Craftsman/Husqvarna parts 165833, 175052, 406712, 176135, and 532175064. Verify your current blade’s part number.
• Center hole: 7/8-inch round, fits most standard spindles. Check your blade’s center hole diameter before ordering.
• Brands: Fits AYP, Craftsman, Husqvarna, and Poulan Pro models with 21" decks from the 1990s onward. Not for zero-turn, riding mowers, or 20" or 22" decks.

Key Things to Know

• Quality: Aftermarket blade, but rated 4.5/5 with 56 reviews. Users report decent durability for residential use, but not as thick as OEM Husqvarna blades.
• Installation: Easy swap – just remove the center bolt, replace blade, and torque to 30-40 ft-lbs. No special tools needed beyond a socket wrench and block of wood to lock the blade.
• Mulching performance: Works well on dry grass; may clump in wet or tall grass. For heavy mulching, consider a dedicated high-lift blade.
• Common gotcha: The 2-pack includes two identical blades. You only need one per mower. Save the second for future replacement or check your mower uses two blades (rare on 21" decks).

Should You Buy It

If you have a 21-inch Craftsman, Husqvarna, or AYP mower and want an affordable mulching blade that’s easy to install and well-reviewed, this 2-pack is a solid value. Skip it if you need a high-lift bagging blade or have a non-standard deck size.