Casio G-Shock GA-B2100 CasiOak vs Orient Mako 40 Green
Two divers compared — $100–$150 vs $250–$500
Quick Verdict
The Casio G-Shock GA-B2100 CasiOak ($100–$150) offers Casio Quartz (Solar-Powered) precision in the tier below the Orient Mako 40 Green ($250–$500). The G-Shock GA-B2100 CasiOak measures 45.4mm (48.5mm lug-to-lug, 11.9mm thick) and is rated 200m (20 ATM). The Mako 40 Green counters with Made in Japan craftsmanship and 200m (20 ATM) water resistance. Both are exceptional divers for their respective tiers.
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Specifications Compared
| Feature | Casio G-Shock GA-B2100 CasiOak | Orient Mako 40 Green |
|---|---|---|
| Price | $100–$150 | $250–$500 |
| Case Size | 45.4mm (48.5mm lug-to-lug, 11.9mm thick) | 40mm |
| Movement | Quartz Module 5689 (Tough Solar + Bluetooth) | Automatic Caliber F6722 |
| Caliber Type | Casio Quartz (Solar-Powered) | Orient In-House Automatic (Hacking, Hand-Winding) |
| Power Reserve | About 7 months on a full charge without light; about 18 months in power-saving (Casio) | 40 Hours |
| Water Resistance | 200m (20 ATM) | 200m (20 ATM) |
| Crystal | Mineral Glass | Sapphire Crystal |
| Case Material | Carbon Core Guard Resin | Stainless Steel |
| Origin | Made in Japan | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Casio's design language vs Orient's approach
The Casio G-Shock GA-B2100 CasiOak features a Carbon Core Guard Resin case at 45.4mm (48.5mm lug-to-lug, 11.9mm thick) with Mineral Glass protection. The Orient Mako 40 Green offers Stainless Steel construction at 40mm with Sapphire Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Quartz Module 5689 (Tough Solar + Bluetooth) vs Automatic Caliber F6722
The G-Shock GA-B2100 CasiOak runs the Quartz Module 5689 (Tough Solar + Bluetooth) (Casio Quartz (Solar-Powered), About 7 months on a full charge without light; about 18 months in power-saving (Casio) power reserve) at standard frequency. The Mako 40 Green uses the Automatic Caliber F6722 (Orient In-House Automatic (Hacking, Hand-Winding), 40 Hours reserve) at 21,600 vph (3 Hz). The Mako 40 Green offers a longer power reserve.
Wearability & Fit
45.4mm (48.5mm lug-to-lug, 11.9mm thick) vs 40mm — different wrist presence
At 45.4mm (48.5mm lug-to-lug, 11.9mm thick), the G-Shock GA-B2100 CasiOak has a bolder wrist presence compared to the Mako 40 Green at 40mm. Water resistance differs: 200m (20 ATM) vs 200m (20 ATM).
Value & Cost of Ownership
Casio sits in the lower tier
The Casio G-Shock GA-B2100 CasiOak sits at $100–$150 and the Orient Mako 40 Green at $250–$500. On the specs that outlast any price: the G-Shock GA-B2100 CasiOak uses Mineral Glass with About 7 months on a full charge without light; about 18 months in power-saving (Casio), against Sapphire Crystal and 40 Hours on the Mako 40 Green. Service intervals are typically 5-7 years for both.
Water Resistance
200m (20 ATM) vs 200m (20 ATM)
The G-Shock GA-B2100 CasiOak is rated to 200m (20 ATM) while the Mako 40 Green handles 200m (20 ATM). Both offer identical water resistance ratings.
Our Verdict
Casio
G-Shock GA-B2100 CasiOak
Choose the Casio G-Shock GA-B2100 CasiOak if you prioritize Casio Quartz (Solar-Powered) engineering, Made in Japan craftsmanship, and 200m (20 ATM) water resistance. At $100–$150, it delivers Quartz Module 5689 (Tough Solar + Bluetooth) with About 7 months on a full charge without light; about 18 months in power-saving (Casio) power reserve.
Check Price on AmazonOrient
Mako 40 Green
Choose the Orient Mako 40 Green if you value Orient In-House Automatic (Hacking, Hand-Winding) technology, Made in Japan heritage, and 40mm proportions. At $250–$500, the Automatic Caliber F6722 with 40 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Casio G-Shock GA-B2100 CasiOak and Orient Mako 40 Green represent two distinct approaches to the diver category — the Casio bringing Made in Japan tradition while Orient delivers Made in Japan engineering.
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How This Page Was Made
Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.