These are examples of decoration / stoppers put on by eureka pen users
These can be purchased for cheap on the internet (see below for more information)
these can be found on the net,
a good source is Aliexpress, Amazon
search for one of these:
-Open ring
-Free size ring
-sterling silver 925 Free size ring
-resin free size ring
***MAKE SURE TO GET THE "OPEN" TYPE ONES
(closed types cannot stretch open, so it is not recommended)
there are various types of materials available for these:
sterling silver, stainless steel, resin, etc.
***If you want to protect the pen from rubbing against the stopper,
you could put a thin "silicone tape" between stopper / cap
or anything you can think of that can fit between the stopper / cap
