Seiko Cal. 6631 - 238

The 6631-238 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6631 caliber with 31j jewels beating at 28,800 bph, it delivers a 71 hours power reserve. [seikata-wm-007feb9b080f]

Also known as: Helmet, Arnie

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

41mm

Case Thickness

13.9mm

Lug Width

18mm

Crystal

Hardlex

Bezel

Coin-Edge

Water Resistance

50m

Dial Color

Champagne

Jewels

31j

Frequency

28,800 bph

Power Reserve

71 hours

Year

1975

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