The Ultra has an internal battery that is rechargeable from any USB power source (solar panel, car port, laptop, etc).  It has an indicator to show when the battery is low.  On a full charge the unit will treat 50L of water. The UV bulb itself, which disassembles the DNA of any nasties in the water, will last up to 8000 activations and after that SteriPEN will replace your unit with a new one (just be sure to register your product with the company when you purchase it).

Using UV light to purify water has been around for decades and is how many municipalities treat their water.  To use the Ultra, simply insert the lamp into your glass or bottle of water, press a button and gently agitate the water until the UV light goes off.  That's the nice part - your water is instantly safe, no waiting around for chemicals to work.  The Ultra has a watertight seal to keep the electronics dry.  Note: use only with clear water, as debris can block the UV light.  If you only have cloudy water with particulates, use a SteriPEN prefilter (sold separately).

Box contains SteriPEN Ultra, USB cable, carrying case, and user's guide.

Weight:  140g (5 oz)
Dimensions:  186 x 43 x 33 mm
Minimum bottle diameter:  20mm
Effective 99.9% against: bacteria, viruses, and protozoan cysts (such as giardia, cryptosporidia)