products that are no longer sold get removed 🙂
so too are the reviews and discussions listed on their product page
the search feature doesn't find all that is here ☚ī¸
old enough to get removed is old enough that someone may need an o-ring
re-posting with a more specific title, using a svoemesto kayfun mini V3 drawing

the o-ring sizes of the ST mini V3 PLUS are
#16 + #18...22x19mm
#9 + #21.....13x11mm
#4 + #10.....10x8mm
#23 + #24.....8x5mm
#20...............8x4mm