A nearly impossible fastener to find in steel, let alone stainless. These are stainless steel 12 point 3/4-16 locking nuts. All new aircraft surplus. I have actually trimmed these down in the past and removed the upper locking portion, to make a standard non locking 3/4″ nut. A multitude of uses on race cars or hot rods. Sold in quantity of 2 per package.