(m3 cap head screws)Made from 18-8 stainless steel, these screws have good chemical resistance and may be mildly magnetic. Length is measured from under the head. (m3X 8mm screws)Metric screws are also known as A2 stainless steel screws. (Long 8mm bolt)Coarse threads are the industry standard; choose these screws if you don’t know the pitch or threads per inch. Fine threads are closely spaced to prevent loosening from vibration. They are not compatible with coarse threads. (Long 8mm screw)Screws that meet ISO 21269 and ISO 4762 (formerly DIN 912) comply with specifications for dimensional standards. 18-8 Stainless Steel Socket Head Screw M3 x 0.5 mm Thread, 8 mm Long,Come wiht a plastic box pack. m3 x 8mm screws,m3 x 8mm，m3 cap head screws