These O rings seals the housing cap / lid to the Big Bubba housing body.
We recommend that the O ring should be replaced every 2 or 3 years.
Although they don't perish quickly, O rings can become compressed or damaged due to dirt ingress around the seal.
That can lead to problems getting and the filter system being out of action while a new O ring is obtained - much better to replace them ar cartridge changeover times.
