Finding the correct stem

[jamesb]

I'm attempting to fix a watch for a friend that has a broken stem but unsure how to size it up with it being a non date watch. I'm unsure what the actual movement is but this is a link to the same movement I believe:

 https://www.ebay.co.uk/itm/364939734599?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=jpPZPpfJTve&sssrc=4429486&ssuid=ixrYkJ6RThm&var=&widget_ver=artemis&media=COPY

It's taken from this watch: https://www.bezali.com/products/rotary-womens-ls03732-06-classic-white-leather-watch?srsltid=AfmBOopT2qUdnXGA5j0Ha3qGV3AjN2HdNywVGWa4dsVYv8ZaY6FSutJF

I was looking at cousins at Chinese stems (I assume it is one) but struggling to understand the diagram of how to measure it up. Can anyone help with this, I've attached an image of the broken stem and the sizing chart.

[AndyGSi]

The square part A and the tip F diameter that's broken off is the place to start.

[mikepilk]

I'm pretty sure that is not a Swiss movement in the ebay link. They probably say Swiss because it's from a Rotary, but they use cheap Chinese skeleton movements. I tried to repair one for a friend, but the quality was so poor, I gave up and just changed the movement - about £25. 

I have never seen a stem on a Swiss movement break there - I can't see how you would break it. I think it says something about the (lack of) quality of the metal. 

Length E is important, but you also need C,A,F to match. Fortunately the Cousins Chinese stems are cheap, so get a couple of the closest.