4G Rotatable OTG Flash Drive USB 2.0 Memory Stick For Cell Phone&Tablet PCs (Black 4G) Chip: Grade A, original Micron brand Material:Environmental protection plastic and Metal 0.5*0.25*2.75in(L*W*H) Supports WINS 7/8/98 / SE /ME / 2000 / XP, Vista and Mac Hot plug & Play;No external power supply requird