[thebosstrx]

To further muddy the waters, I used to work in a fastener company on the trade counter. People often complained that the driver bits we sold were garbage as they chewed out. Some stuff is mesured in "Rockwells " which is a mesurable degree of hardness and the theory is that the driver bit should be less rockwells than the fastener so you don't chew out the phillips head in the screw. Easier to use another driver bit than try to remove a chewed out screw. Unfortunately the manufacturer (China or India) don't know or don't care how many Rockwells their product is. Hope this has added some mud.