Found these blades on AliExpress. 10 blades for about $1.7 plus shipping. Thought I'd give em a try. Tried one in my Rockwell 6c plt5. The #5 plt is not a plt I can shave everyday with. I ended up with a nice smooth shave with no irritation. Three passes with, across, and against the grain. Some buffing also. I would rate it as a DFS. The against the grain wasn't as close as I usually get with plt4 but the trade off was less irritation. Tomorrow will try this blade with plt6.