[francogt]

Those are replacement tips. I broke the head, leaving the shaft inside the pen and thats what I'm not able to get out. It seems to be a common problem if you look at the reviews:

https://www.amazon.com/dp/B0713VCDPY

[criddell]

You can buy them from Amazon Japan (and they will ship to the US):

https://www.amazon.co.jp/-/en/Sony-DPTA-RS1-Stylus-Pen-Cores...