Hamilton Khaki Field Automatic vs Seiko 5 Sports GMT SSK001
Hamilton's field watch meets Seiko's GMT watch
Quick Verdict
The Seiko 5 Sports GMT SSK001 ($250–$500) delivers Seiko In-House Automatic GMT technology in the tier below the Hamilton Khaki Field Automatic ($500–$1,000). The 5 Sports GMT SSK001 measures 42.5mm and is rated 100m (10 ATM). The Khaki Field Automatic justifies its premium with Swiss Made heritage and Automatic H-10. Both represent excellent choices in the luxury watch category.
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Specifications Compared
| Feature | Hamilton Khaki Field Automatic | Seiko 5 Sports GMT SSK001 |
|---|---|---|
| Price | $500–$1,000 | $250–$500 |
| Case Size | 38mm | 42.5mm |
| Movement | Automatic H-10 | Automatic Caliber 4R34 (True GMT) |
| Caliber Type | Automatic (ETA C07.611 base) | Seiko In-House Automatic GMT |
| Power Reserve | 80 Hours | 41 Hours |
| Water Resistance | 100m (10 ATM) | 100m (10 ATM) |
| Crystal | Sapphire Crystal | Hardlex Crystal |
| Case Material | Stainless Steel | Stainless Steel |
| Origin | Swiss Made | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Hamilton's design language vs Seiko's approach
The Hamilton Khaki Field Automatic features a Stainless Steel case at 38mm with Sapphire Crystal protection. The Seiko 5 Sports GMT SSK001 offers Stainless Steel construction at 42.5mm with Hardlex Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Automatic H-10 vs Automatic Caliber 4R34 (True GMT)
The Khaki Field Automatic runs the Automatic H-10 (Automatic (ETA C07.611 base), 80 Hours power reserve) at 21,600 vph (3 Hz) frequency. The 5 Sports GMT SSK001 uses the Automatic Caliber 4R34 (True GMT) (Seiko In-House Automatic GMT, 41 Hours reserve) at 21,600 vph (3 Hz). The Khaki Field Automatic edges ahead on power reserve.
Wearability & Fit
38mm vs 42.5mm — different wrist presence
At 38mm, the Khaki Field Automatic wears more compactly on smaller wrists compared to the 5 Sports GMT SSK001 at 42.5mm. Water resistance differs: 100m (10 ATM) vs 100m (10 ATM).
Value & Cost of Ownership
Seiko sits in the lower tier
The Hamilton Khaki Field Automatic sits at $500–$1,000 and the Seiko 5 Sports GMT SSK001 at $250–$500. On the specs that outlast any price: the Khaki Field Automatic uses Sapphire Crystal with 80 Hours, against Hardlex Crystal and 41 Hours on the 5 Sports GMT SSK001. Service intervals are typically 5-7 years for both.
Water Resistance
100m (10 ATM) vs 100m (10 ATM)
The Khaki Field Automatic is rated to 100m (10 ATM) while the 5 Sports GMT SSK001 handles 100m (10 ATM). Both offer identical water resistance ratings.
Our Verdict
Hamilton
Khaki Field Automatic
Choose the Hamilton Khaki Field Automatic if you prioritize Automatic (ETA C07.611 base) engineering, Swiss Made craftsmanship, and 100m (10 ATM) water resistance. At $500–$1,000, it delivers Automatic H-10 with 80 Hours power reserve.
Check Price on AmazonSeiko
5 Sports GMT SSK001
Choose the Seiko 5 Sports GMT SSK001 if you value Seiko In-House Automatic GMT technology, Made in Japan heritage, and 42.5mm proportions. At $250–$500, the Automatic Caliber 4R34 (True GMT) with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Hamilton Khaki Field Automatic and Seiko 5 Sports GMT SSK001 represent two distinct approaches to fine watchmaking — the Hamilton bringing Swiss Made tradition while Seiko delivers Made in Japan engineering.
Frequently Asked Questions
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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.