Earlier U.S. military vehicles, used from World War I through the Vietnam War, used a scheme of "olive drab", often with large white stars. Prototypes, early production M1 (105 mm gun) and M1-IP models switched to a flat forest green paint scheme. The large white insignia stars have also transitioned to much smaller black markings. Some units painted their M1s with the older Mobility Equipment Research and Design Command (MERDC) 4-color paint scheme but the turn-in requirements for these tanks required repainting them to overall forest green. Therefore, even though a large number of the base model M1s were camouflaged in the field, few or none exist today. M1A1s came from the factory with the NATO three color camouflage Black/Med-Green/Dark-Brown Chemical Agent Resistant Coating (CARC) paint jobs. Today, M1A1s are given the NATO three color paint job during rebuilds. M1s and M1A1s deployed to Operation Desert Storm were hastily painted desert tan. Some, but not all, of these tanks were re-painted to their "authorized" paint scheme. M1A2s built for Middle Eastern countries were painted in desert tan. Replacement parts (roadwheels, armor skirt panels, drive sprockets, etc.) are painted olive green, which can sometimes lead to vehicles with a patchwork of green and desert tan parts. Australian M1A1s were desert tan when delivered but have undergone a transition to the Australian Army vehicle standard 'Disruptive Pattern Camouflage'; a scheme that consists of black, olive drab, and brown. The U.S. Army can equip its Abrams tanks with the Saab Barracuda camouflage system, which provides concealment against visual, infrared, thermal infrared, and broad-band radar detection. Concealment The turret is fitted with two six-barreled M250 smoke grenade launchers (USMC M1A1s used an eight-barreled version), with one on each side. When deployed, the grenades airburst, creating a thick smoke that blocks both visual and thermal imaging. The engine is also equipped with a smoke generator that is triggered by the driver. When activated, fuel is sprayed into the hot turbine exhaust, creating the thick smoke. Due to a risk of fires however, this system is sometimes disabled. Armor In July 1973, representatives from Chrysler and General Motors traveled to the United Kingdom, and were escorted by personnel from the Ballistic Research Laboratory and XM1 Project Manager Major General Robert J. Baer to witness the progress of British developed Chobham armor. They observed the manufacturing processes required for the production of Chobham armor, which was an