Where is the booster of the RPG-7 contained?

The booster of the RPG-7 is indeed contained within a cardboard wax tube. This design is intentional, as the cardboard material offers a lightweight and cost-effective solution while also providing the necessary protection for the booster during transportation and storage. The wax coating helps to provide some level of moisture resistance, ensuring that the booster remains functional until it is ready for use.

Furthermore, the cardboard construction aligns with the overall design philosophy of the RPG-7, which prioritizes practicality and ease of use in a combat environment. This makes it easier for soldiers to handle and deploy the weapon without the added weight that would come from using more robust materials. Other materials listed in the options do not provide the same combination of benefits, such as weight, cost-effectiveness, and protective qualities.