Every metal CasiOak traces its DNA back to the original GA-2100, which itself united two design languages: the octagonal case of 1983's DW-5000C — G-Shock's very first watch — with the analog display of the AW-500, the brand's first analog model. The GM-B2100D-1AJF takes that lineage further than any prior metal variant, rebuilding the bezel, pushers, screw-back case, and bracelet entirely from stainless steel rather than mixing metal with resin.
A three-pronged lug structure disperses shock to where the band connects to the case, backed by G-Shock's signature resin buffering inside — full metal construction without sacrificing the impact resistance the brand is built on. Tough Solar charging and Bluetooth smartphone link carry over from the resin GA-B2100, wrapped in a case rated to 200m water resistance. It's the watch that proved a full-metal G-Shock could still be a G-Shock in every functional sense, not just in looks.
