Seiko introduced its first sports watch in 1959 for mountaineers who needed a tool they could trust at altitude. The Alpinist SPB505 carries that lineage into a 39.5mm hardened stainless steel case, a black dial with signature Arabic numerals, wedge-shaped indices, and LumiBrite hands built for low-light readability. A rotating inner compass bezel handles navigation. The sapphire crystal has anti-reflective coating on the inner surface, and a screwdown crown and caseback deliver 660 feet of water resistance. Inside, the automatic Caliber 6R55 beats at 21,600 vibrations per hour with a 72-hour power reserve and manual winding capability. The Alpinist mountain symbol is visible through the transparent caseback.