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Seiko 4R15

4R15 and 4R16 are two related automatic upper-midrange watch movements from Seiko.

Overview

The 4R15 family was introduced in 2008 as mainstream automatic watch movements for Seiko watches. It is based on the hacking/hand-winding Seiko 6R15 but lacks these advanced features. Both of these movement families are based on the basic Seiko 7S26 movement, and all share some components. Unlike the 7S26 family (and the hacking/hand-winding brother, 4R35/6/7/8/9), the 4R15/16 have a long 50 hour power reserve thanks to an advanced Spron 510 mainspring. This is shared with the 6R15 as well.

Variants

Like most Seiko movements, the 4R15/16 family operate at 21,600 A/h. All models feature sweep hour, minute, and second hands. The 4R15 features a date window, while the 4R16 has both day and date in a window. Both have 22 jewels.

Movement Beat Hands Date Subdial Jewels Power reserve
4R15 21,600 A/h Hour, minute, seconds Date None 22 50 hours
4R16 Day and date

Applications

The 4R15 and 4R16 are used in many Seiko “Superior” watches, most in the “SRP” model series. These featured upmarket features from the common Seiko 5 line, such as sapphire crystals and metal bracelets with solid end links.

Seiko 7S Family

The following movements were all based on the Seiko 7S26 movement.

Group Year
Introduced
Movements Mainspring Hacking/
Hand-winding
7S 1996 7S25, 7S26, 7S35, 7S36, 7S55 Traditional No
6R1x 2006 6R15, 6R20, 6R21, 6R24 Spron 510 Yes
4R1x 2008 4R15, 4R16 Spron 510 No
4R3x 2011 4R35, 4R36, 4R37, 4R38, 4R39, 4R71 Traditional Yes

Description:

Functions:

Data:

  • 22 jewels
  • 21,600 A/h
  • Power reserve 41 hours
  • Spron 510 mainspring

Production period: