SECURITY PATTERN U.S. Army Staff Sgt. Christopher Welch provides security from a Stryker armored vehicle during a convoy to Robat, Afghanistan, March 19, 2010. U.S. soldiers, assigned to Troop B, 8th Squadron, 1st Cavalry Regiment, are constructing a checkpoint for the Afghan highway police. SHARE: Download: Full Size (0.08 MB) Credit: VIRIN: 453150-I-SBD29-188.jpg Photo Gallery