Seiko, beloved by collectors old and new, made a name for itself over the decades by issuing utilitarian watches that, one by one, found cult followings. Two of Seiko’s most well known product lines are Prospex and Alpinist. The modern day Prospex line encompasses above-entry level sport watches, while Alpinist has been around since 1959. The modern Prospex Alpinist watches combine the two namesakes’ durability and good looks. The SPB377 and SPB379 are the blue and black dial references that make up Seiko’s current catalog of a longtime fan favorite.

The watches are made of stainless steel with Seiko’s proprietary hardening coating. They measure 39.5mm wide, 46.4mm lug to lug, and 13.6mm thick. Water resistance is 200 meters (660 feet) despite the exhibition caseback, which showcases the Seiko caliber 6R54. The watches feature glossy dials with Seiko’s signature Alpinist handset. An additional GMT hand reaches the outer edges of the dial and works in conjunction with the steel outer 24-hour bezel. A date window is discreetly tucked away at 4:30. A dual crown setup allows the rotation of the inner bezel for navigation, which is a longtime highlight of the Alpinist line. Both watches come with color-matched leather straps.

The SPB377 and SPB379 are powered by Seiko’s in-house caliber 6R54. Announced in 2023, it is the first GMT movement featured in a Prospex watch. Automatically and manually wound, the 6R54 beats at 21,600 vph and offers a substantial 3-days of power reserve. Seiko rates the movement to -15/+25 seconds a day in normal temperature conditions (5 - 35 degrees C).