Rotary&reg; Lawn Mower Blade Fits John Deere Models D100 LA100 SST15 Replaces OEM AM137328 GX22151 GY20850 For 42 Deck Rotary replacement blade fits John Deere Windsor Husqvarna AM137328 AM137333 AM141033 GX22151 GY20850, 50-3231, 578431915 2 Blades Required for a 42" Deck or 3 Blades Required for a 42 Deck Quantity: Pack Rotary Mower Blades manufactures high-quality, OEM replacement lawn mower blades