ST9120411AS - Seagate 120GB 7200RPM SATA 3Gb/s 2.5-inch Hard Drive

G-Force Protection When a laptop is dropped, the most catastrophic damage to the hard drive occurs when the head scrapes across the surface of the disk, causing potential data loss. G-Force Protection, an optional dropsensor, protects the Momentus 7200.3 drive against shock by sensing when the systemis in a free-fall state, moving the heads off the platter and locking them in place'all within three-tenths of a second.