A portable locking device (10) (110) for securing a computer disk drive unit which incorporates cooperating interlocking units engaging means (16) (18), (90) (112), one (16) (112) of which hooks onto the unit through the drive unit and slot (13) (82), the other (18) being in a pivotal relationship with the first engaging means (16) (112) and both engaging means having complementary locking members to lock the means together.
