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Seiko Prospex Alpinist Mechanical
Ref. SPB123J1
Case
- Diameter
- 39.5mm
- Thickness
- 13.2mm
- Lug-to-lug
- 46.4mm
- Lug width
- 20mm
- Material
- Stainless Steel
- Water resistance
- 200m
- Caseback
- See-through screw case back
Crystal & dial
- Crystal
- Sapphire
- Dial colour
- Cream
- Indices
- Applied gold Arabic numerals at 12/2/4/6/8/10 with applied gold triangular batons at the remaining hours
- Lume
- Lumibrite on hands and indexes
Movement
- Caliber
- Seiko 6R35
- Type
- Automatic
- Jewels
- 24
- Hacking
- No
- Hand-winding
- No
- Complications
- Date, Hacking seconds, Internal rotating compass bezel
Seiko
Seiko's upgraded automatic caliber offering a substantial 70-hour power reserve, nearly double the 4R35 it replaces in higher-end Presage and Prospex models. The extended reserve is achieved through a longer mainspring while maintaining the same 21,600 vph beat rate. Accuracy is tightened to -15/+25 seconds per day compared to the 4R35's wider tolerance. Represents Seiko's push to compete with Swiss movements offering 80-hour reserves.
PROSPEX collection · 4 watches
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In a nutshell
The Seiko Prospex Alpinist Mechanical (ref. SPB123J1) is an automatic watch, with a 39.5mm stainless steel case, 13.2mm thick, powered by the Seiko 6R35 movement and a Approx. 70 hours-hour power reserve. Water resistance is rated to 200m, under a sapphire crystal, with date, hacking seconds, internal rotating compass bezel complications.
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