Seiko SSB421P1

The Seiko reference SSB421P1 is a chronograph with a 39.5 mm steel case. The case carries a water-resistance rating of 100 metres. The movement is quartz calibre 8T67, which has a battery life of approximately 36 months. The dial has a date display; the hands and indices carry LumiBrite. The movement is visible through a display back; movement accuracy is plus or minus 15 seconds per month. Magnetic resistance is 4,800 A/m; the lug width measures 20 mm. Elapsed time is measured in increments of 1/5 second. A sapphire crystal covers the dial.