What should you inspect on the Scott PBE during preflight?

The correct choice focuses on the humidity gauge for color change, which is a critical indicator of whether the Scott Protective Breathing Equipment (PBE) is ready for use in an emergency situation. The humidity gauge indicates the moisture level in the PBE. A color change signals that the PBE may have been compromised or that it is not suitable for use, as the device must maintain a specific moisture level to function properly. This inspection is essential to ensure that the equipment will provide adequate protection to the user when needed.

In addition to inspecting the humidity gauge, it's important to consider other factors such as normal wear and tear and the presence of a visual instruction manual. Inspecting for normal wear and tear ensures that the PBE is physically intact and functioning as intended. The visual instruction manual is also an important feature as it provides guidance for operating the equipment. However, while these aspects are important during an inspection, they do not carry the same immediacy as checking the humidity gauge, which directly affects the ability of the PBE to perform in emergency situations.