Suunto Core is an ABC-watch (A=altitude, B=barometer, C=compass). Since its release in 2007 there has been more than 30 different versions of Core. All of them have the same functions, but their external appearance differ. Most versions have plastic frames, but some are made of aluminum and two of them are made of stainless steel. Most of the Core versions are no longer in production. There are some limited, numbered editions of Core, such as Everest Edition (8848 made, in honor of Apa Sherpa's 21 ascents on Mount Everest), Red Bull X-Alps Edition (864 made, according to the length of the race), and Extreme Edition (3000 made). Suunto celebrated its 75th anniversary by releasing Anniversary Edition (in some countries known as Alpine edition). Core All Black is often erroneously referred to as Core All Black Military or Core Military, but such nominations are not official and such military versions do not exist. Core is said to have named after its including core elements needed in this type of watch.