What must be intact for the POB to be considered ready for use?

The correct answer, which is the tamper seal, is crucial because it serves as an indicator that the portable oxygen bottle (POB) has not been previously accessed or tampered with since it was last inspected or filled. When a tamper seal is intact, it provides assurance to users that the equipment is in a state that meets safety and operational standards. This is particularly important in emergency situations, where the reliability and integrity of the equipment are critical.

While factors such as oxygen supply, pressure gauge, and oxygen mask are important components of the POB’s functionality, without the tamper seal being intact, there may be doubts regarding the POB’s readiness or integrity. Verification of the tamper seal is typically part of pre-flight or pre-use checks to ensure that the equipment can be relied upon in an emergency.