
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.
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Prospex Sea collection · 32 watches
4 colorways
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The community take
Owners widely praise the Seiko Prospex Sea for its robust build, classic dive watch design, and excellent value, with many highlighting its strong lume and comfortable wearability. Reviewers consistently flag its superior bezel action and overall finishing as standout features for its price point. Some owners find the 43mm case size substantial, with one noting it felt big, thick, and heavy on a 6.5-inch wrist, though others consider it a perfect size. The movement's power reserve is noted as less than newer variants by one reviewer. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its classic design and robust build at an accessible price.
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The matchups people make with the Seiko Ice Diver most — open one to see it side by side.
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