Personna 74 blades are amazing. They were produced in the early 70s and were made in both DE and injector varieties. The decades of the 1960s and 70s were arguably the era of some of the best blades ever made. I think the Personna 74 is the crown jewel of that golden age of blade production. These blades were made with tungsten steel for extreme hardness and then coated with titanium for a very smooth finish. I am using one in a blue-tip SuperSpeed and the shaves are close and comfortable. The really amazing thing is the durability of the 74s. I am up to 19 shaves on one blade and it feels as if it is still on shave #3. It just won't quit. I have put it into semi-retirement so I can use some of my other blades for awhile. I plan to go back to it soon and find out just how long the darn thing will last. If you have not tried Personna 74 blades they are well worth seeking out.