Seiko Cal. 6637 - 907

The 6637-907 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6637 caliber with 22j jewels beating at 36,000 bph, it delivers a 70 hours power reserve. [seikata-wm-bb5f6fc02e9d]

Also known as: Bullhead

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

39mm

Case Thickness

13.8mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

170m

Dial Color

Green

Jewels

22j

Frequency

36,000 bph

Power Reserve

70 hours

Year

1975

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