Pro-Grade Corundum Sharpening Stones: Crafted with industrial-grade corundum, these 4 sharpeners resist wear and tear even under heavy use. The dual-layer design (coarse + fine grit) tackles rust, nicks, and dull edges in seconds, restoring blades to razor-sharp precision—extend mower lifespan and reduce engine strain! Universal Blade Balancer for Flawless Performance: Includes a Model 42-100-compatible balancer with adjustable steps (fits 5/8"-1.5" blades). Test balance post-sharpening to eliminate vibrations—protect bearings, ensure smoother cuts, and prevent costly mower damage. No wobble = longer blade life! 10-Second Drill Installation, Effortless Sharpening: Universal 1/4" shank snaps into ANY drill (electric or hand-powered). No tools needed—secure in 10 seconds, sharpen in minutes. for DIYers: skip manual filing and save hours! Multi-Tool Versatility: Beyond Mower Blades: Sharpen garden shears, rototiller blades, sickles, and more. Compact size fits tight spaces, while corrosion-resistant materials withstand outdoor use. A year-round tool saver! Complete 5-Piece Kit, Ready for Action: Get 4 heavy-duty sharpeners (2 gray dual-layer, 2 blue single-layer) + 1 Metal balancer. Durable storage case keeps parts organized—ideal for garages, workshops, or on-the-go maintenance. No extra purchases needed!