The o-rings that seal the thread between the HP system and the marker are only too happy to be replaced by conventional o-rings. The consequence of this is usually a lively wear and tear of these conventional seals.
This Urethane Teflon Oring is the right solution for this. This is made of Teflon and is therefore somewhat harder and more wear-resistant than conventional rubber rings.
Of course, both work, you will change less often (almost never if handled correctly) with this high-quality Teflon ring.
