Seiko launches three new Prospex Alpinist stainless-steel watches, refreshed with 6R55 movement

Three new Seiko Prospex Alpinist models - SPB503, SPB505, and SPB507 - have been announced for release this November, pushing a series that originated in 1959 as a field watch for Japanese mountaineers. These latest Alpinists use Seiko’s new 6R55 automatic movement, with 72 hours of power reserve.

• The SPB503 features a blue dial and stainless steel bracelet, positioned at £880 (~$1,177).
• The SPB505 has a black dial with a stainless steel case and bracelet, set for the same release window.
• The SPB507 has a green dial with a steel case and leather strap, priced at £800 (~$1,070).

Each watch is 39.5 mm in diameter, 12.7 mm thick, and 46.4 mm lug-to-lug, with a 20 mm lug width. They feature sapphire crystals with magnifiers, anti-reflective coating, and water resistance to 20 bar. All models include a rotating compass bezel, screw-down crown, and see-through case backs.

Technical features

• Movement: 6R55, automatic, 24 jewels, manual winding, precision rated at +25 to -15 seconds/day.
• Case: Stainless steel with super-hard coating (steel bracelet) or cow leather (strap).
• Magnetic resistance: 4,800 A/m.
• Weight: Bracelet model 147g, leather model 88g.

The Alpinist was first developed in 1959 for Japanese "Yama-otoko" - mountain men - making it one of Seiko’s oldest sport watch series. Its defining features have always been its solid build, compass bezels, and legibility. After several generations, including landmark models such as the 1995 SARB series, it is nice to see that Seiko is still working on evolving the Alpinist as a modern field watch.

Buy the Seiko SNKL45 on Amazon.