This is a classic model Seiko chronograph using the popular (now discontinued) V657 movement. It's a highly accurate 1/10th second 60 minute timer but still has a centre second hand. All chrono functions are on the sub-dials. They made this model in half a dozen different colour variants. Most commonly seen are the blue dial and silver dial, but they did a few which are a little harder to find. Orange is the rarest, this grey/green model is hard to find too. Serial number gives this a production date of January 1999. 40mm total diameter including the crown. Stainless steel crown and ...