The original GA-2100 built its reputation on an octagonal resin case that drew comparisons to far pricier luxury watches. The GM-2100 takes that same silhouette and rebuilds it with a forged stainless steel case — circular-brushed on top of the bezel, polished along the sides and lugs — mounted over a shock-absorbing resin inner case that keeps the original's durability intact.
It sits below Casio's full-metal GMB-2100, which adds Bluetooth connectivity, solar charging, and an integrated bracelet at a significantly higher price point. The GM-2100 skips those extras but keeps the core appeal: a metal CasiOak at roughly a third of the full-metal version's cost, without giving up the shock resistance and 20 ATM water resistance that made the original resin version a sleeper hit in the first place.
