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Seiko Presage SSA425 Open Heart vs Seiko 5 Sports 5KX
Two timepieces compared — $250–$500 vs $250–$500
Quick Verdict
The Seiko Presage SSA425 Open Heart ($250–$500) and Seiko 5 Sports 5KX ($250–$500) are closely matched timepieces at similar price points. The Presage SSA425 Open Heart emphasizes Seiko In-House Automatic engineering while the 5 Sports 5KX focuses on Made in Japan craftsmanship.
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Specifications Compared
| Feature | Seiko Presage SSA425 Open Heart | Seiko 5 Sports 5KX |
|---|---|---|
| Price | $250–$500 | $250–$500 |
| Case Size | 40.5mm | 42.5mm |
| Movement | Automatic Caliber 4R38 | Automatic Caliber 4R36 |
| Caliber Type | Seiko In-House Automatic | Seiko In-House Automatic |
| Power Reserve | 41 Hours | 41 Hours |
| Water Resistance | 50m (5 ATM) | 100m (10 ATM) |
| Crystal | Hardlex Crystal | Hardlex Crystal |
| Case Material | Stainless Steel | Stainless Steel |
| Origin | Made in Japan | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Seiko's design language vs Seiko's approach
The Seiko Presage SSA425 Open Heart features a Stainless Steel case at 40.5mm with Hardlex Crystal protection. The Seiko 5 Sports 5KX offers Stainless Steel construction at 42.5mm with Hardlex Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Automatic Caliber 4R38 vs Automatic Caliber 4R36
The Presage SSA425 Open Heart runs the Automatic Caliber 4R38 (Seiko In-House Automatic, 41 Hours power reserve) at 21,600 vph (3 Hz) frequency. The 5 Sports 5KX uses the Automatic Caliber 4R36 (Seiko In-House Automatic, 41 Hours reserve) at 21,600 vph (3 Hz). Power reserves are closely matched.
Wearability & Fit
40.5mm vs 42.5mm — different wrist presence
At 40.5mm, the Presage SSA425 Open Heart wears more compactly on smaller wrists compared to the 5 Sports 5KX at 42.5mm. Water resistance differs: 50m (5 ATM) vs 100m (10 ATM).
Value & Cost of Ownership
Same tier — different value propositions
The Seiko Presage SSA425 Open Heart sits at $250–$500 and the Seiko 5 Sports 5KX at $250–$500. On the specs that outlast any price: the Presage SSA425 Open Heart uses Hardlex Crystal with 41 Hours, against Hardlex Crystal and 41 Hours on the 5 Sports 5KX. Service intervals are typically 5-7 years for both.
Water Resistance
50m (5 ATM) vs 100m (10 ATM)
The Presage SSA425 Open Heart is rated to 50m (5 ATM) while the 5 Sports 5KX handles 100m (10 ATM). The 5 Sports 5KX offers superior water resistance.
Our Verdict
Seiko
Presage SSA425 Open Heart
Choose the Seiko Presage SSA425 Open Heart if you prioritize Seiko In-House Automatic engineering, Made in Japan craftsmanship, and 50m (5 ATM) water resistance. At $250–$500, it delivers Automatic Caliber 4R38 with 41 Hours power reserve.
Check Price on AmazonSeiko
5 Sports 5KX
Choose the Seiko 5 Sports 5KX if you value Seiko In-House Automatic technology, Made in Japan heritage, and 42.5mm proportions. At $250–$500, the Automatic Caliber 4R36 with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Seiko Presage SSA425 Open Heart and Seiko 5 Sports 5KX represent two distinct approaches to the timepiece category — the Seiko bringing Made in Japan 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.