Seiko Cal. 6331 - 428

The Seiko 6331-428 represents an important milestone in Seiko's 1973 lineup. Powered by the 6331 caliber with 25j jewels beating at 21,600 bph, it delivers a 70 hours power reserve. [seikata-wm-01179084d585]

Also known as: UFO, Bellmatic

Specifications

Movement

Automatic

Case Material

Gold-Plated

Case Width

41mm

Case Thickness

12.0mm

Lug Width

20mm

Crystal

Mineral

Bezel

Coin-Edge

Water Resistance

150m

Dial Color

Green

Jewels

25j

Frequency

21,600 bph

Power Reserve

70 hours

Year

1973

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