The Hustler fusion blades never cease to amaze me. I put a worn out set on a while back to rough cut some areas. When I say worn out, I am talking about the sail on the back of the blade vitually gone. My wife was cutting normal grass (I should have already changed the blades, but had not), and I was watching her, I thought to myself, that mower is flying. She was cutting wide open on a Hustler Super Z (15 mph), with completely demolished blades. She was cutting at a low height (2.75") and absolutely flying, most people say you cannot cut grass at 15 mph with perfect blades and do a decent job. I actually took the mower and finished cutting some areas she is a little afraid of. I got on the mower and started cutting, and was in an area where I could run possible 10 mph. I heard what I knew to be a deformed blade under the deck, as well as feeling some vibration. I finished cutting in about 15 minutes and there was absolutely no grass left standing anywhere, or none that looked different in any way. I took the mower to the shed and snatched it up in the air, got a new set of blades, took the 18 volt Dewalt impact wrench, zipped them off and put the new set on. I started looking at the old blades and thought to myself, there is no way these blades could possibly have been cutting grass and doing a good job. I will try and make a picture of the old blades, if I remember. The sails were virtually gone, with one being ripped out partially, this is what was causing the different sound from the blades turning. These fusion blades on a Hustler Super Z are truly unbelievable, for the length of time they last, as well as being able to continue giving a very respectable cut while being demolished. I personally; will always pay the higher price for this type blade.