Sellita Caliber SW400-1

The Sellita caliber SW400-1 is essentially the big brother to the popular SW200-1 movement.

This caliber can be used in larger diameter watches without the need for a movement spacer. You could say it is a big size ETA 2824-2 clone.

In Sellita’s own words:

“The SW400-1 has all the benefits of the precision, reliability and robustness of the SW200-1 but with an increased diameter size of 31.00 mm. This large diameter is a perfect fit for men’s watches in contemporary sizes (40 to 46 mm diameter).

The SW400-1 comes with a date display 44% larger compared to the SW200-1. The placement of the date is also optimised. Located more to the outside of the dial, the date window allows for larger-sized dials in a balanced design.

Due to its 31.00 mm size, the SW400-1 can fit perfectly into large diameter casings without the need to resort to a spacer ring. It also allows to have a larger see-through case back in line with the diameter of the casing.
Also the aesthetic of the movement is very pleasant owing to its bigger plate and new oscillating weight, which allows for a variety of customisations thanks to its large diameter.” -Sellita

Accuracy Rating:

Expected average accuracy of the SW400-1 depends on the grade of movement in your watch (read the Sellita Movement Grades page to learn more).

SW400-1 Variations:

There are two variations of the SW400-1, with the main difference being the calendar complication (date).

• SW400-1 a – Date at 3:00
• SW400-1 b – No date

The SW400-1 b is a proper no date 3-hander with only one crown position for setting the time – unlike when watch brands try to make a no date watch with the ETA 2824-2, causing the phantom date phenomenon.

Power Reserve:

Sellita’s official documentation on the calibre SW 400-1 has some inconsistencies when it comes to listing the power reserve. The tech sheets state 38 hours of power reserve on a full wind, however, their website listing states a typical power reserve of 41 hours. Therefore, you can expect to get somewhere between those figures when the watch is fully wound. Please share your power reserve experience in the comments below so that the community and get a better idea of actual power reserve.

Editor’s note: this is not the only area where the manufacturer lists specs that don’t match up. They also list the SW400-1 as being 13.75”’ on one page, then 14”’ on another.

Crown/Stem Removal:

Which position should the crown be in?

Official Sellita documentation states that the crown should be in the time setting position before being extracted.

What tool should be used to extract the crown/stem?

Use a 1mm screw-driver to press the detent button. Avoid using tweezers or any other tool with a point because this could jam the setting lever and damage the setting lever spring.

Additional Resources:

• Official SW400-1 Tech Sheets (pdf)
• List of Sellita movements