The Orient caliber F4902 is a self-winding automatic movement with 21 jewels. Orient makes their movements in-house in Japan. This is a non-hacking and non-handwinding movement. You may have seen other sites list this movement incorrectly as caliber F49-02 or F.4902, but Orient officially writes the caliber number as F4902.
F4902 VS 46943:
The Orient caliber F4902 is said to be an upgrade to the caliber 46943. The main difference is that the older 46943 has a pusher on the side (2:00) to change the calendar (day of the week), while the newer F4902 calendar can be corrected via the crown.
The Orient caliber F4902 has a power reserve of 40 or more hours.
Setting the date:
Avoid setting the date on your F4902 watch within the hours of 8:00pm to 4:00am.