Military trucks are definitely an integral part of the armies. They are used to transport weapons, vehicles or other cargo, can serve as a command post, a platform for the installation of various weapons and other things. Military vehicle indicates any vehicle for land-based military transport and activity, including combat vehicles; both specifically designed for, or significantly used by military and armed forces. Most military vehicles require off-road capabilities and/or vehicle armour (plate), making them heavy, therefore some have vehicle tracks instead of being wheeled vehicles; and half-tracks have both. Furthermore, some military vehicles are amphibious, constructed for use on land and water, and sometimes also intermediate surfaces. Military vehicles are almost always camouflaged, or at least painted in inconspicuous color(s). In contrast, under the Geneva Conventions, all non-combatant military vehicles, such as field ambulances and mobile first aid stations, must be properly and clearly marked as such. Under the conventions, when respected, such vehicles are legally immune from deliberate attack by all combatants. Historically, militaries explored the use of commercial off-the-shelf (COTS) trucks and vehicles, both to gain experience with commercially available products and technology, and to try and save time in development, and money in procurement. A subtype that has become increasingly prominent since the late 20th century is the improvised fighting vehicle, often seen in irregular warfare.