Nickname decoder
What watch is the "CasiOak"?
The "CasiOak" is the nickname for Casio's G-Shock GA-2100 line, whose octagonal case echoes the Audemars Piguet Royal Oak. The version in this catalogue is the GA-B2100-1A: a 45.4 mm Carbon Core Guard resin case, 48.5 mm lug to lug and 11.9 mm thick, module 5689 with Tough Solar and Bluetooth, 200 m (20 ATM) water resistance, in the low-hundreds band.
What the nickname refers to
The name is a blend of Casio and Royal Oak, and it attaches to the whole GA-2100 family: the original battery-powered GA-2100 and the GA-B2100 that adds Tough Solar charging and Bluetooth phone connection. The catalogue lists the GA-B2100-1A, the black solar-and-Bluetooth version, and its figures are the ones on this page.
What the nickname does not tell you is that this is a full G-Shock underneath: Carbon Core Guard resin case, 200 m water resistance, and the thinness the octagonal case is known for at 11.9 mm. Casio quotes about seven months of running on a full charge without light and about eighteen months in power-saving mode.
GA-2100 or GA-B2100
The B in GA-B2100 marks the Bluetooth-and-solar version; it is the one to choose if you never want to change a battery and want the phone to set the time. The plain GA-2100 is the cheaper battery-powered original with the same case. The catalogue documents the GA-B2100; the comparisons below put it against the square DW-5600 and the Citizen Tsuyosa, which is the pairing people actually ask assistants about.
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Frequently Asked Questions
Why is the GA-2100 called the CasiOak?
Because its octagonal bezel echoes the Audemars Piguet Royal Oak, so the community blended Casio and Royal Oak into one word. Casio does not use the name.
Is the CasiOak solar?
The GA-B2100 version is: Casio's Tough Solar with about seven months of running on a full charge without light. The original GA-2100 runs on a battery.
How big is the CasiOak?
Casio lists the GA-B2100 at 45.4 mm across, 48.5 mm lug to lug and 11.9 mm thick. It wears smaller than the width suggests because of the short lugs.
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