A standard NATO marker that is a red upside down triangle with a white horizontal stripe warns you of?

The marker that is a red upside-down triangle with a white horizontal stripe is specifically used to indicate the presence of boobytraps. This distinctive symbol is part of NATO's standardization for visual warnings and serves to alert personnel to the potential danger posed by hidden or disguised explosive devices that are triggered by the action of the victim. Understanding these visual cues is critical for maintaining awareness and safety in environments where enemy forces may employ such tactics.

In military operations, recognizing this specific marker contributes to avoiding unexpected injuries and casualties, as boobytraps are often used to impede movement and create psychological effects on forces. Thus, being aware of the meaning behind this marker is essential for operational security and the safety of personnel in the field.