Since its release in 1983 the toughness watch G-SHOCK which has continued to evolve in search of insatiable strength is a model with a bright red accent color on the classic black. - G-SHOCK's brand colors of black and red have been incorporated into the popular standard model. - Uses Octagon Case Bluetooth - R Solar GA-B2100It has a cool design that can be used in a wide range of ways with a coloring that accentuates the burning red color. ・Shock-resistant structure ・Tough solar (solar charging system)・ 20 ATM water resistance・ Mobile link function (function interlocking with compatible mobile phones via Bluetooth communication)・ Needle retraction function (when the needle overlaps with the liquid crystal display and is difficult to see the needle can be temporarily retracted from above the liquid crystal display) *When not linked with a smartphone normal quartz accuracy (average monthly difference ± 15 seconds) works・ World time: 38 cities around the world (38 time zones with automatic summer time setting function) + UTC (Coordinated Universal Time) time display home time city replacement function・ Stopwatch (1/100 second (less than 1 hour) / 1 second (more than 1 hour) 24 hour counter with lap/split)・ Timer (set unit: 1 second maximum set: 60 minutes measured in 1 second units)・ 5 time alarms ・Time signal ・Battery indicator display ・Power saving function・ Full auto calendar・ 12/24 time system display switching・ Operation sound ON/OFF switching function・ Date display (month/day display switching)・ Day of the week display (6 languages: English Spanish French German Italian Russian)・Double LED light: LED light for dial (with super illuminator afterglow function afterglow time switch (1.5 sec/3 sec)) LED backlight for LCD (super illuminator afterglow function afterglow time switch (1.5 sec)) second/3 seconds))・Automatic time adjustment ・Easy clock setting ・About 300 cities in world time ・Time &place ・Reminders - Compatible with our designated i - Phone and Android smartphones - Please check the website for details such as devices whose operation has been confirmed and OS compatibility. *Limited to devices equipped with Bluetooth* Bluetooth is a registered trademark of Bluetooth SIG Inc.*"i - Phone"is a trademark or registered trademark of Apple Inc. registered in the United States and other countries. *"Android"and "Android logo"are trademarks or registered trademarks of Google LLC. *Other company names and product names are trademarks or registered trademarks of their respective companies. *GA-B2100BNR is certified by the Radio Law of Japan. * Regarding the mobile link function it depends on the specifications of the mobile phone itself and the service of the carrier of the country of use and it varies from individual to individual.