DIN – Deutsches Institut für Normung (German Institute for Standards) The vast majority of metric fasteners are presently manufactured to this standard which was created long before ISO standards. There are DIN standards for just about everything. DIN standards are currently being revised to more closely match ISO standards. For ordering fasteners all you need is The DIN( which defines the style of the fastener) The material desired (i.e. 8.8 Steel, 316 Stainless, Hastelloy C276) The coating or plating (if any) ISO – International Standard Organization Founded in 1946 this organization publishes standards which individual countries have to vote on and are asked to apply. Currently ISO is comprised of more than 90 member countries. ISO’s standards for metric fasteners are rapidly gaining more recognition and in the years to come will probably become the world standard. ANSI – American National Standard Institute A US organization that has developed standards which are essentially in agreement with ISO standards. JIS – Japanese Industrial Standard Although mainly based on DIN, some standards have been modified based on the needs of the Japanese market. Fasteners used in most electronic equipment manufactured in Japan fall under the JIS standard. All of the standards listed above detail an items’ dimensional specifications and material content. These standards are accepted worldwide and ensure you that any items that are ordered according to a particular standard will meet the specifications in compliance to the listed standards regardless of the manufacturer. Although there are many different standards for metric they are all manufactured to the same thread. The DIN spec may call for a certain head dimension and ANSI spec another but a 10×1.25 ANSI hex bolt will always thread into a DIN 10×1.25 hex nut and vice versa.