The U.S. Army has quietly issued detailed instructions on how to armor hummers and other vehicles. Included are technical details on what size and type (thickness and hardness) of steel plate will provide what degree of protection. The instruction material has been sent to all units (especially reserve and National Guard) that are preparing to go to Iraq or Afghanistan. It is left up to the unit commanders to decide if they want to armor their vehicles, or wait for the lighter, and easier to install, armor kits the army is buying and distributing. The army has already bought 3,400 vehicles that were armored while being manufactured, as well as thousands of armor kits for hummers already in use. Many units are going to parts of Iraq and Afghanistan where there has been little or no violence, and may not get the kits. But commanders, especially National Guard, are under pressure from their troops to have some armored hummers available. The instructions are "for official use only" and are thus not available to the public.