Seiko Cal. 5640 - 644

The 5640-644 is a sought-after Hand-Winding piece from Seiko's golden era. It features a Burgundy dial protected by a Mineral crystal and offers 200m of water resistance. [seikata-wm-8b04f123e595]

Also known as: Sumo

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

36mm

Case Thickness

10.9mm

Lug Width

21mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

200m

Dial Color

Burgundy

Jewels

36j

Frequency

21,600 bph

Power Reserve

42 hours

Year

1982

Related Models

• Seiko 3899-648
• Seiko 0764-213
• Seiko 7043-202
• Seiko 6671-887
• Seiko 3891-176
• Seiko 4479-195
• Seiko 6248-652
• Seiko 0737-214
• Seiko 7168-927
• Seiko 3836-592
• Seiko 4558-590
• Seiko 4594-598