Seiko Cal. 5640 - 425

The Seiko 5640-425 represents an important milestone in Seiko's 1965 lineup. It features a White dial protected by a Sapphire crystal and offers 50m of water resistance. [seikata-wm-1d3808e05d0c]

Also known as: Helmet

Specifications

Movement

Solar

Case Material

Hardlex-Coated Steel

Case Width

37mm

Case Thickness

9.5mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

50m

Dial Color

White

Jewels

28j

Frequency

28,800 bph

Power Reserve

48 hours

Year

1965

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