Which of the following is NOT a size available for the Advanced Combat Helmet?

The Advanced Combat Helmet (ACH) is available in a range of sizes to accommodate different head sizes for optimal fit and comfort. The sizes typically provided include Medium, Large, and Extra Large. These sizes are designed to ensure that personnel can achieve a secure fit, which is crucial for the helmet's effectiveness in providing protection and support.

The XXL size is not commonly included in the standard size options for the ACH. This helps to clarify that while the other sizes are part of the official sizing chart, XXL is not recognized as a standard size for this specific helmet model. Understanding the nuances of helmet sizing is important as it contributes directly to the effectiveness of personal protective equipment in combat situations.