A contact system includes at least one first contact, at least one second contact, and at least one movable contact. The processor is programmed to generate at least one of time-based or event-based messages relating to at least one of flow generator operation, flow generator service, flow generator use, patient health, peripheral devices and services, patient treatment, and reminders. The radial bearing assembly includes an outer member having an outer profile arranged and designed to cooperate with a complementary profile in the interior of the turret insert tube so that the outer member is turned by the turret insert tube when the vessel rotates about said turret, without fixed attachment of the outer member to the turret insert tube.