Seiko TMI SII caliber PC21S movement

Hattori SII Caliber PC21S

Seiko TMI SII caliber PC21S movement

Manufacturer Hattori aka Seiko Instruments Inc. (SII)
Caliber Number PC21S
Type Quartz
Size 18.5mm x 3.15mm thick (overall height 4.8mm)
Battery Cell Number SR626SW
Frequency 32,768 hz
Quartz Type Tuning fork type quartz crystal
Stem 354222 / tap 10
Hand Sizes 1.20 / .70 / .17mm
Jewels 0
Functions Hours, minutes, seconds
Country of Manufacture Singapore
Known Models Most cheap quartz watches from China. Add yours to the comments below.

The Seiko Instruments caliber PC21S is a 0 jewels quartz movement found in many ultra-entry level timepieces.


You might find this caliber listed as being produced by Hattori aka Epson aka TMI (Time Module Inc) aka Seiko Instruments Inc. We’re not sure why all the different names, but sure they all lead back to Seiko. Learn more about this here.


The documentation from Time Module states an accuracy of “Less than 30 seconds per month at normal temperature range.”

Replacement Prices

Replacement prices of $7.95 were found online at the time of this post.

Official Documentation

  • Official TMI tech sheets and drawings here

Is the Hattori SII Caliber PC21S any good? Share your opinions, experiences and watches below... Keep comments respectful and follow our community guidelines.

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20 dollars or less, let's see them! - Page 408

[…] took the photo sharp enough to zoom in: (still hardly readable) It's a PC21S, made in Singapore, according to this site (first hit in google…don't know how dependable the info is), it leads back to Seiko. […]


And by “Most cheap quartz watches from China” you do mean fake watches right?


Fake only if they try to sell it as something it isn’t. I’ve bought a few that were very open about Made In China, shipped from China. Nothing fake about it, it was a Chinese watch.


Thank you for the info on this, I saw this movement in the Curren model 8266 and I had wondered who the manufacturer was. Excellent quality for the cost of this budget timepiece! Even though it is one of Seiko’s cheaper movements, the quality is still going to be much better than a lot of the other Chinese quartz movements that use plastic gears.


One of the names of these cheap Chinese quartz watches was TWINS. After 20 years, mine is still quite pecise though, about 2 seconds per week.

Olivia Gabriela Ruginosu
Olivia Gabriela Ruginosu

Of mine is write Gucci quartz , is very old and has the same thing on the back like this one . So it’s fake yeah ?

Jerry's Watch Frenzy
Jerry's Watch Frenzy

I don’t know but probably. This mechanism is used in many fakes.


Tengo uno Montreal Carlo q dice en la tapa Japón eso es bueno?