HT B1FE1061 HD Med Lift Single Mower Blade for 61″ Ferris iCD Decks 510755 XHT Lawn Mower Replacement Blade. XHT (Xtreme Hardness & Toughness) blades are 25-40% harder than standard lawn mower blades. The benefits of XHT blades are sharper, longer lasting cutting edges. Greater bending resistance. Tighter aftermarket tolerances than OEM. XHT blades also have greater impact strength. 61″ cutting blades. Fits new iCD Decks. Center Hole: 5/8″ Length: 21″ Thickness: .250 Type: Medium Lift – Notched Width: 2-1/2″