Coba, a 3-year-old chocolate lab trained to detect tactical explosives, chews on a tennis ball as David Sheffer, her handler and dog trainer, explains Coba's capabilities at the National Training Center on Fort Irwin, Calif., June 14, 2012. Soldiers assisgned to the 2nd Division's 4th Stryker Brigade, role players and government civilians watched the demonstration. Brigade members will select handlers to lead a similar dog in Afghanistan when they deploy this fall.