What two components are checked during the preflight of the POB on the ERJ?

During the preflight check of the Portable Oxygen Bottle (POB) on the ERJ, it's crucial to ensure that the mask tubing and protective plug are properly inspected. This is important because the mask tubing must be free of kinks or damage to ensure proper oxygen flow, and the protective plug prevents contamination and damage to the oxygen outlet before it's needed. Ensuring these components are in good condition helps guarantee that the POB is functional and ready for use in an emergency situation.

In the context of the other options, checking only the connection of the mask does not cover the necessary safety protocols, as it neglects the condition of the tubing. Considering the weight of the POB and its location is not specific to a thorough preflight check of the system's readiness. Similarly, while verifying the connection to the seat and PSI level is important, it does not encompass the critical aspects of both the mask tubing and the protective plug that need to be assessed for optimal safety and performance.