The 650 mAh batteries are rated for 8 hours but, depending how much you're vaping, may last longer before needing a recharge.  The taller 1100mAh batteries are rated to last 12+ hours.  Torpedo batteries are 510-threaded and feature a blue led ring that lights when the button is pressed.

From the bottom of the battery's port to the bottom of the battery itself, the 650mAh battery is 65mm in length, the 1100mAh battery is 83mm in length.