The Timex M33 watch movement was introduced during the period of 1948-1950. It featured a Breguet hairspring and was part of the first line of automatic movements to include a triple calendar function. The specific differences between the 225M and the 228 are not known. Noteworthy features of this movement include its automatic (bumper) winding system, sweep second hand, and the ability to display the day, date, and month. The date hand can be set using a pusher at 8 o'clock, while the month can be set using a pusher at 9:20 o'clock.

The Timex M33 features the following functions:

• Automatic (bumper)
• Date hand: set by pusher at 8h
• Day
• Month: set by pusher at 9:20h
• Sweep second