Which device is used to detect liquid chemical agents?

The correct choice is M-8 and M-9, which are devices specifically designed for the detection of liquid chemical agents. The M-8 paper is utilized to identify certain nerve agents and blister agents by changing color when it comes into contact with these chemicals. The M-9 tape complements this by providing a similar detection capability, indicating the presence of certain chemical agents through a color change as well.

These devices are critical in military and emergency response situations, providing quick and reliable identification of potentially hazardous substances. Properly using these detection tools allows operators to take appropriate measures to protect personnel and minimize the risk of exposure to harmful chemicals. Their importance lies in their ability to provide immediate guidance on the presence of liquid chemical warfare agents, ensuring safety and informed decision-making in the field.

In contrast, the other options consist of devices that are not specifically meant for detecting liquid chemical agents. Therefore, they do not fulfill the requirement of detecting such substances as effectively as the M-8 and M-9 devices do.