http://www.steripen.com/emergency-product/
The Emergency is strong, sturdy and reliable. You can consistently rely on the Emergency to provide you with access to safe drinking water in a time of crisis. Affordable and efficient, the Emergency purifies 200 half-liter servings of water on just one set of AA lithium batteries, enough to see your family comfortably through any problem time.
The Emergency is designed to fit perfectly into commercial water bottles, forming a seal that lets you keep the water in the original bottle for purification. Just insert the Emergency securely into the mouth of the bottle, turn it upside down, and you have safe drinking water in less than a minute.
