Airman Matthew Desrochers, an Explosive Ordnance Disposal Preliminary Course student with the 342nd Training Squadron, carefully prepares a block of C-4 for detonation during training at the EOD proficiency range on Lackland's Training Annex. The six-day EOD proficiency course teaches ordnance familiarization and screens students for entry into the seven-month technical school at Eglin Air Force Base, Fla. (USAF photo by Robbin Cresswell)