SMK XS /QB/TH 5 X front cap Tough seals
These are Tougher and harder for the XS 78 models.
This is a pack of 5 High Quality harder O rings and a small sachet of Moly 33 O ring lube. These fit the front cap and Brass valve body.
It is wise to Check and or change these on a regular basis to ensure that you don't waste your Co2.