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.
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.
|4R15||21,600 A/h||Hour, minute, seconds||Date||None||22||50 hours|
|4R16||Day and date|
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.
|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|