When I looked it up it said my mower had a 60 inch belt which goes from the PTO on the engine to the deck itself. When the belt arrived it was a 57 inch belt according to the number on it... I called them up about that and they said that was normal the develop was measured on the inside diameter which is shorter than the outside diameter. It did go on okay but it lasted only an hour or two I think I have a belt tensioner alignment issue... so I'm going to need another and appreciate to opportunity to get a 10 % discount for the review. As their price was less than half of what I was quoted at the car parts place.