Casio G-Shock GA-B2100 CasiOak vs Hamilton Khaki Aviation Pilot Auto
Casio's diver meets Hamilton's pilot watch
Quick Verdict
The Casio G-Shock GA-B2100 CasiOak ($100–$150) offers Casio Quartz (Solar-Powered) precision in the tier below the Hamilton Khaki Aviation Pilot Auto ($1,000–$1,500). The G-Shock GA-B2100 CasiOak measures 45.4mm (48.5mm lug-to-lug, 11.9mm thick) and is rated 200m (20 ATM). The Khaki Aviation Pilot Auto counters with Swiss Made craftsmanship and 100m (10 ATM) water resistance. Both are exceptional watches for their respective tiers.
Transparency — We earn a small commission on purchases made through our Amazon links. This doesn't affect our editorial independence.
Specifications Compared
| Feature | Casio G-Shock GA-B2100 CasiOak | Hamilton Khaki Aviation Pilot Auto |
|---|---|---|
| Price | $100–$150 | $1,000–$1,500 |
| Case Size | 45.4mm (48.5mm lug-to-lug, 11.9mm thick) | 38mm |
| Movement | Quartz Module 5689 (Tough Solar + Bluetooth) | Automatic H-10 (ETA 2824-2 base) |
| Caliber Type | Casio Quartz (Solar-Powered) | Hamilton/ETA Automatic |
| Power Reserve | About 7 months on a full charge without light; about 18 months in power-saving (Casio) | 80 Hours |
| Water Resistance | 200m (20 ATM) | 100m (10 ATM) |
| Crystal | Mineral Glass | Sapphire Crystal |
| Case Material | Carbon Core Guard Resin | Stainless Steel |
| Origin | Made in Japan | Swiss Made |
Category-by-Category Analysis
Design & Aesthetics
Casio's design language vs Hamilton'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 Hamilton Khaki Aviation Pilot Auto offers Stainless Steel construction at 38mm with Sapphire Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Quartz Module 5689 (Tough Solar + Bluetooth) vs Automatic H-10 (ETA 2824-2 base)
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 Khaki Aviation Pilot Auto uses the Automatic H-10 (ETA 2824-2 base) (Hamilton/ETA Automatic, 80 Hours reserve) at 21,600 vph (3 Hz). The Khaki Aviation Pilot Auto offers a longer power reserve.
Wearability & Fit
45.4mm (48.5mm lug-to-lug, 11.9mm thick) vs 38mm — 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 Khaki Aviation Pilot Auto at 38mm. Water resistance differs: 200m (20 ATM) vs 100m (10 ATM).
Value & Cost of Ownership
Casio sits in the lower tier
The Casio G-Shock GA-B2100 CasiOak sits at $100–$150 and the Hamilton Khaki Aviation Pilot Auto at $1,000–$1,500. 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 80 Hours on the Khaki Aviation Pilot Auto. Service intervals are typically 5-7 years for both.
Water Resistance
200m (20 ATM) vs 100m (10 ATM)
The G-Shock GA-B2100 CasiOak is rated to 200m (20 ATM) while the Khaki Aviation Pilot Auto handles 100m (10 ATM). The G-Shock GA-B2100 CasiOak is better suited for water activities.
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 AmazonHamilton
Khaki Aviation Pilot Auto
Choose the Hamilton Khaki Aviation Pilot Auto if you value Hamilton/ETA Automatic technology, Swiss Made heritage, and 38mm proportions. At $1,000–$1,500, the Automatic H-10 (ETA 2824-2 base) with 80 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Casio G-Shock GA-B2100 CasiOak and Hamilton Khaki Aviation Pilot Auto represent two distinct approaches to fine watchmaking — the Casio bringing Made in Japan tradition while Hamilton delivers Swiss Made engineering.
Frequently Asked Questions
More Comparisons
Explore These Watches
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.