Seiko Cal. 5631 - 646

The Seiko 5631-646 represents an important milestone in Seiko's 1989 lineup. With its 22mm lug width and 15.5mm profile, it sits comfortably on most wrists. [seikata-wm-84616f0404e8]

Also known as: Tuna, Baby Tuna

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

45mm

Case Thickness

15.5mm

Lug Width

22mm

Crystal

Mineral

Bezel

Coin-Edge

Water Resistance

30m

Dial Color

Silver

Jewels

23j

Frequency

36,000 bph

Power Reserve

52 hours

Year

1989

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