====== SPRON ======
**SPRON** is a proprietary spring alloy developed by [[Seiko]] and the Institute for Materials Research, Tohoku University.

It is a special alloy of Cobalt and Nickel developed for mechanical watch springs. Characteristics include high elasticity, durability, corrosion resistance, and heat resistance. It is comparable to [[Nivarox]], produced by [[Swatch Group]] and used by a majority of Swiss watch makers.

Seiko is one of only a few watch makers with its own [[mainspring]] production, along with [[Swatch Group]], [[Rolex]], and [[A. Lange & Söhne]].

  * SPRON 100 is the basic alloy of Cobalt, Nickel, Iron, Chromium, and other metals.
  * SPRON 510 is used by many modern midrange and higher Seiko movements. It is an alloy of Cobalt, Nickel, Chromium, Molybdenum and other metals.
  * SPRON 610 is a more advanced alloy, used in Seiko's [Spring Drive]] and [[Seiko 9S55|Grand Seiko Mechanical]] movements with 72 hour [[power reserve]].

===== See also =====
  * [[Nivarox]]


{{tag>Watch_materials Abbreviations Seiko}}