of the Panzer. Some US tanks had spare tracks attached to their armour. This was done with the M4 Sherman and Stuart tanks. Besides spare track-links, other improvised armour included wooden logs, tree trunks, armour plating from other destroyed or abandoned tanks and even a thick layer of concrete, albeit the lattermost very rarely. Concrete was sometimes added above the driver to protect the thinner roof above a driver from antitank rifle fire coming from above. Soviet tank crews sometimes welded bed frames to their tanks to protect against shaped charge explosives such as the German Panzerfaust anti-tank weapon. The bed frames were an early version of modern slat armour, which was used in the 2000s to protect tanks against rocket-propelled grenades such as the RPG-7. During the North African Campaign, the German Afrika Korps attached strips of spare tracks to the front of their Panzer IIIs and Panzer IVs. Elsewhere, such as on the Eastern Front and in Italy, the German military also relied on add-on plates of armour of varying thickness (including the well-known Schürzen add-on side armour plating), cement and timber to increase the armour of their tracked combat vehicles, especially those with weaker armour like the Marder series of self-propelled anti-tank guns and the StuG III (many of these were given either timber, concrete, additional armour plating or spare tracks to increase their battlefield survivability). Most German vehicles exported to their allies in the war also carried such forms of armour, such as StuG IIIs sent to Finland, which carried both log (on the sides) and concrete (frontally) armour. Vietnam War In the Vietnam War, U.S. gun trucks were armoured with sandbags and locally fabricated steel armour plate. The Troubles in Northern Ireland See Improvised tactical vehicles of the Provisional IRA Iraq War In post-invasion Iraq, improvised vehicle armour is colloquially referred to as "hillbilly armour", "farmer armour" or "hajji armour" by American troops. During the occupation that followed the 2003 invasion that toppled Saddam Hussein's regime, insurgent forces deployed roadside bombs, RPG teams, and snipers with small arms to attack military vehicles on supply convoys and other known routes. To protect themselves from these threats, American troops began reinforcing their Humvees, LMTVs and other vehicles with whatever was available, including scrap metal, kevlar blankets and vests, compromised ballistic glass and plywood. In some cases they relied on Iraqis to assist them in these efforts, and