U.S. Army soldiers from, Alpha Company, 1st Battalion, 21st Infantry Regiment, 2nd Stryker Brigade Combat Team, 25th Infantry Division, Schofield Barracks, Hawaii kneel down behind a concrete barrier after throwing a M67 fragmentation grenade, Sept. 19, 2012, during grenade qualification training at Pohakuloa Training Area, on Hawaii's Big Island. Soldiers from 1st Battalion, 21st Infantry Regiment, are conducting a monthlong exercise at PTA which is focused on platoon level collective training with enabler integration. The training will culminate in a combined arms live-fire exercise later this month.