The Miyota caliber 1M02 is part of the 1L/1M family of affordable quartz calibers. The 1M02 is a 0 jewels quartz movement that is made in Japan. This caliber is a replacement for the Citizen caliber 1102.
Some of the topics covered in this caliber listing:
1M02 VS 1M12:
Miyota makes a similar caliber 1M12. The main difference when comparing the two is that the 1M12 only has a date while the 1M02 also has a bilingual day of the week complication.
1M02 Accuracy Rating:
Miyota states the accuracy of this movement to be +/-20 seconds/month when “worn under normal circumstance”.
The cal. 1M02 takes an SR621SW (364) watch battery. The battery is said to last up to 3 years. There is a battery saving (aka hacking) mode by pulling out the stem into time setting mode (position II). When doing this, the seconds hand will stop and the power consumption will be limited. Below is a view of the empty battery tray. No insulator film is necessary since the base is plastic.
At the time of this post the replacement price of a new Miyota calibre 1M02 is around $7.95 – $9.50 USD.
The good thing about the small, cheap Miyota movements is that they can usually be interchanged with similar calibers (eg: Miyota 20XX / 21XX / 6LXX / 6MXX) if you can’t find a replacement, or if you want to add or remove additional features to modify an existing watch.