Final answer:
A mechanical latch or locking mechanism allows the towbar of an MHU-110 trailer to be stowed in a vertical position, and some models may include a pneumatic assist for this purpose.
Step-by-step explanation:
The MHU-110 trailer is an equipment piece used by the military to transport munitions. The feature that allows a towbar to be stowed in a vertical position typically involves a mechanical latch or locking mechanism that secures the towbar once it's folded upwards. This mechanism is crucial to ensure the towbar remains stowed during movement, thus preventing any accidental deployment or snagging. Due to variations by model or manufacture, some may include a pneumatic assist to help raise and secure the towbar, easing the physical burden on the operator.