Transcend 320GB StoreJet M2 External HDD Military-Grade Shock Resistance Military-Grade Shock Resistance - Designed to meet U.S. military drop test standards Advanced 3-stage shock protection system. Combines a rugged slip-resistant silicone outer shell, a reinforced hard casing, and an internal hard drive suspension damper. Easy-grip silicone rubber shell. Silicone is both soft to the touch yet easy to grip and less likely to slip and fall during travel 2.5-Inch SATA HDD One Touch Backup USB 2.0