When do the O-rings in the mounting adapter type SUN, UN and UNG need a replacement?

Non-greased end pieces can destroy the O-rings in the mounting adapters relatively quickly, in which case an exchange is necessary. In general, only the first two rings in the adapter are affected in such cases. Should an exchange be necessary, (? leak test), we provide a replacement tool and replacement rings with which the O-rings can be exchanged. --> 'The O-rings in the mounting adapter are defective. Where can I find replacements and how do I change them?'