4GB - You will love the combination included with the Laser Pointer Flash Drive. This item is made up of an integrated laser pointer and flash drive which easily pull apart. Laser pointer can transmit a beam up to 100' away. The unique design allows you to use the laser pointer when the flash drive is in use. The USB drive is compatible with Windows ME/2000/XP/98/SE/Vista and Mac OS 9.x. For your convenience batteries are also include.