The G-Shock GST-B400MV-5A and Baby-G MSG-B100MV-5A are part of the “Mars and Venus” concept series. The G-Shock GST-B400MV-5A evokes Mars with its reddish copper ion plating, while the Baby-G MSG-B100MV-5A evokes Venus with its gold ion plating.
These watches are available separately and feature stainless steel bezels and body parts, brown resin bands, Tough Solar power, and Bluetooth smartphone link. Both models are fully shock-resistant. The GST-B400MV-5A is water-resistant to 200 meters, and the MSG-B100MV-5A is water-resistant to 100 meters.
The watches will be released in October 2021 in Asia, but they were not announced for Japan yet. The GSTB400MV-5A is expected to be released in the U.S. for $390, but the status of the MSG-B100MV-5A there is unknown.
Update: The GST-B400MV-5AJF (58,300 yen) and MSG-B100MV-5AJF (35,750 yen) will be released in November 2021 in Japan.