Arnold 490-110-0056 Murray 20-3/8-Inch Lawn Mower Blade 2-Pack 91871HT This blade replaces OE #91871HT. Fits 40" Murray lawn tractors (Contains 2 blades). This is a duplicate of the original equipment blade that came on your mower/tractor from the factory. Arnold quality replacement blades fit exactly the mower/tractor they are manufactured for. Check the original equipment number to locate the correct replacement duplicate blade.