Seiko Cal. 6640 - 543

The Seiko 6640-543 represents an important milestone in Seiko's 1975 lineup. It features a Navy dial protected by a Sapphire crystal and offers 50m of water resistance. [seikata-wm-664d1e5ea949]

Also known as: Sumo

Specifications

Movement

Quartz

Case Material

Two-Tone

Case Width

35mm

Case Thickness

10.1mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

50m

Dial Color

Navy

Jewels

27j

Frequency

21,600 bph

Power Reserve

53 hours

Year

1975

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