Each Tungsten cone needle is about 6/8" long; 0.059 inches (1.49mm) in diameter. Each needle is inspected through a microscope for sharpness and smooth sides. These are used in cutting machines like Presto/Rek-O-Kut cutters, etc. They are used for embossing into polycarbonate. Feel free to look at the link above that shows a recording where one of my needles was used Thanks!!!