Seiko 7A28

The Seiko 7A28 is a quartz chronograph movement manufactured in Japan. It contains 15 jewels, operates on an SR936SW battery with approximately two years of life, and claims accuracy within ±15 seconds per month. The movement is notable for its all-metal construction with no plastic components, making it repairable and serviceable, and includes a rotary step switch for fine-tuning accuracy. It was introduced in the Sports 100 line in the early 1980s and has since been discontinued.