I have two RS 612's, one for the front and one in the rear. I've used them for 3 years and resharpen my own blades as many folks do. I bought this blade by accident, not realizing it was the low cut blade. Now that Fall is here and the new grass has thickened the yard substantially, I put a set of these on the front mower. Wow!Most blades, just come as stamped out....sharp but no edge. These have a wicked edge!I am impressed, you will be too. Be careful though, those plastic guards on the blade edges are there for a reason, don't cut yourself!Special K