Seiko SSB421

The Seiko reference SSB421 is a chronograph with a 39.5 mm steel case. The case is 11.6 mm thick, with a lug-to-lug measurement of 46.6 mm and a water-resistance rating of 100 metres. Quartz calibre 8T67 has a battery life of approximately 36 months. Over the dial is a sapphire crystal; the dial has a date display. 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. The hands and indices are luminous.