SteriPen Water Bottle Pre-Filter
The SteriPEN Pre-Filter filters fits on Nalgene and other 32 ounce wide-mouth water bottles and filters out particulates and debris. When in use, pour water through the durable 4040 micron screen filter cartridge to fill the bottle. Then you're ready to purify the water with a SteriPEN UV water purifier. Remove the filter cartridge from the Pre-Filter, insert the SteriPEN into the center of the filter, flip the bottle, and agitate the water until the SteriPEN indicates the treatment is complete.