We use the Seiko NH35A in our kits, used by numerous large and small brands all over the world. The movement has 24 Jewels, beats with 21,600 beats per hour and has a power reserve of 40 hours. The movement is automatic winding with a bi-directional rotor on the back which will be driven by the movement of your wrist.
The NH35 has three crown positions:
Position 0: Fully pushed into the movement, you can manually wind the movement. Turn the crown away from you (clockwise) to charge the main spring. After 55-60 turns the main spring should be charged.
Position 1: Pull the crown out to its first position to set the date via the quick-setting function. You will now move the date disc directly. It is recommended not to set the date between 9pm and 4am, as your main drive train will have engaged with the date disc already.
Position 2: Time-setting function - Pull out the crown all the way to the second position to set your time. You will also automatically engage the date disc by skipping over midnight (24h cycle). In position 2 your movement will stop, the so called hacking feature of the movement. This enables you to set your time exactly down to the second.