Milsim is short for military simulation. It is usually a type of airsoft game often consisting of several hundred players usually wearing a standardized uniform and loadout for whichever side in the game they are playing so they are recognizable to their teammates, and in turn adds to the realism of the event. Milsim events can sometimes last several days, and are often very expensive to get ready for depending on what kind of gear you need for the event. So the gear required for milsim events need to be robust and dependable. They also typically outperform other similar products since they take more of a beating at a milsim event than a standard pick-up game at a local airsoft field.