Battery - Streamlight Lithium CR123A - 85175
I know they are on the market but you cannot use them with Streamlight Flashlights and keep your warranty. Streamlight is converting many of their flashlights to work with Streamlight's 18650 batteries linked below. If you have a specific flashlight you are wondering about please let me know.
That is the price for 1. Here is the URL for a 12 pack:
It is about half the size of a C battery.