Updated
Hamilton Khaki Field Mechanical vs Seiko 5 Sports
Hand-wound Swiss or self-winding Japanese
Quick Verdict
The Hamilton Khaki Field Mechanical ($500–$1,000) is a 38mm Swiss hand-wound field watch with sapphire, an 80-hour reserve and 50m. The Seiko 5 Sports SRPD55 ($250–$500) is a 42.5mm Japanese automatic with Hardlex, a 41-hour reserve, a day-date and 100m. The Hamilton is the purer, smaller watch; the Seiko is cheaper and more water-ready.
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Specifications Compared
| Feature | Hamilton Khaki Field Mechanical 38mm | Seiko 5 Sports 5KX |
|---|---|---|
| Price | $500–$1,000 | $250–$500 |
| Case Size | 38mm | 42.5mm |
| Movement | Hand-Wound H-50 (ETA 2801-2 base) | Automatic Caliber 4R36 |
| Caliber Type | Hamilton/ETA Hand-Wound | Seiko In-House Automatic |
| Power Reserve | 80 Hours | 41 Hours |
| Water Resistance | 50m (5 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
Field watch against dive-style sports watch
The Hamilton is a traditional field watch with no date, just time. The Seiko 5 Sports is a dive-style sports watch with a rotating bezel and a day-date window. If the query is "field watch", the Hamilton is the real thing; the Seiko is a sports diver.
Movement & Performance
Hand-wound 80 hours against automatic 41 hours
The Hamilton runs the hand-wound H-50 (ETA 2801-2 base), 17 jewels at 21,600 vph, with an 80-hour reserve. You wind it by the crown. The Seiko runs the automatic 4R36, 24 jewels at 21,600 vph, with a 41-hour reserve, winding itself as you wear it. The Hamilton runs nearly twice as long on a full wind.
Durability & Water Resistance
Sapphire on the Hamilton, 100m on the Seiko
The Hamilton has a sapphire crystal and a 50m rating. The Seiko has Hardlex, Seiko's hardened mineral glass, and a 100m rating. The Hamilton resists scratches better; the Seiko is better for swimming.
Wearability & Fit
The Hamilton is 4.5mm smaller
The Hamilton is 38mm and the Seiko is 42.5mm. The Hamilton fits small wrists easily and looks right with almost anything. The Seiko is a larger sports watch.
Value & Cost of Ownership
The Seiko is a band cheaper
The Seiko 5 Sports sits in the $250–$500 band and the Hamilton in $500–$1,000. The Hamilton buys you Swiss build, sapphire and a long reserve. The Seiko buys you an automatic with a day-date and 100m for less.
Our Verdict
Hamilton
Khaki Field Mechanical 38mm
Choose the Hamilton Khaki Field Mechanical if you like the ritual of winding a watch and want a classic small field watch. Sapphire, an 80-hour reserve and a 38mm case are the draws. Note it has no date and is rated to 50m.
Check Price on AmazonSeiko
5 Sports 5KX
Choose the Seiko 5 Sports if you want an automatic that winds itself, shows the day and date, and handles swimming at 100m. It costs less and is the more practical daily watch, though it is the larger of the two.
Check Price on AmazonThe Bottom Line
The Hamilton Khaki Field Mechanical is a 38mm Swiss hand-wound watch with a sapphire crystal and an 80-hour power reserve, while the Seiko 5 Sports SRPD55 is a 42.5mm Japanese automatic with a 41-hour reserve, a day-date and double the water resistance at 100m, in a lower price band.
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.