In 2006, the later Alpinists like the SARB013, SARB015 and SARB017 were introduced and became an instant success; especially the SARB017. Each identification number represents a different colour, cream, black and green. The SARB017 (green) model became by far the most popular because it is unique and can be worn in literally any situation, business or casual. The other two variations (especially the creme SARB013) are now much harder to find, possibly making them more valuable today.
All of the 2006 models use an 6R15 Automatic Diashock 23 Jewel movement, provide 20 Bar water resistance and have gold plated hands and numbers. These three models are the longest running models and continue to gain popularity because of their elegance and versatility. There are only a few subtle differences between the three watches. For example, both the cream and green versions use a more traditional hand system with a cathedral hour hand while the black version uses a more modern look which compliments the intense colouring.
Seiko as of 2013 has upgraded the 6R15B movement to 6R15C. The upgrade includes:
1) Added one jewel on main plate, barrel hole (6R20 has that jewel already)
2) Modified ratchet sliding spring
3) Modified date indicator maintenance plate
4) New balance wheel
5) New barrel
This 2019 Alpinist features another upgrade, the 6R35 caliber, a display caseback but has much the same dial design as the Red Alpinist 4S15.. Some believe this is the ultimate Alpinist vibe in a modern form..