Seiko Cal. 5631 - 904

Seiko 5631-904

The 5631-904 is a sought-after Automatic piece from Seiko's golden era. The Coin-Edge bezel and 41mm case give it a distinctive presence on the wrist. [seikata-wm-b6b2e928df8d]

Also known as: Helmet, Baby Tuna

Specifications

Movement
Automatic
Case Material
Two-Tone
Case Width
41mm
Case Thickness
13.6mm
Lug Width
18mm
Crystal
Hardlex
Bezel
Coin-Edge
Water Resistance
100m
Dial Color
Burgundy
Jewels
27j
Frequency
36,000 bph
Power Reserve
43 hours
Year
1991

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