Which artifact is not typically part of military vehicle equipment?

The correct choice identifies luxury sound systems as an artifact that is not typically part of military vehicle equipment. Military vehicles are designed primarily for functionality, ruggedness, and mission readiness, rather than comfort or luxury features. Essential equipment is focused on safety, emergency preparedness, and operational capability.

In contrast, reflective triangles are used for safety and visibility in case of breakdowns, first aid kits are crucial for medical emergencies, and fire extinguishers are vital for fire safety in the event of an incident. These items directly support the operational integrity and safety requirements inherent in military operations, emphasizing practicality and readiness over non-essential comforts.