The German supplier of ceramic armor for the Stryker LAV caused a stir when it was revealed that the composition of the ceramic had been changed without letting the army, or the American manufacturer of the Stryker, know. Samples of the new plates were then tested and ten of eleven plates passed the test (not being penetrated by a Russian 14.5mm machine-gun bullet.) The problem with the one plate can be fixed at the unit level (adding another metal plate to those of the size that was penetrated.) One of the Stryker brigades is going to Iraq next month. When it gets there, "slat armor" (a heavy duty metal grid) will be placed around the vehicle, to make RPG warheads detonate prematurely, and not penetrate the Stryker. This form of protection was developed during World War II, shortly after RPGs were invented. In Vietnam, troops often improvised, sometimes actually using chain link fence outside their armored vehicles.