Katadyn Steripen Pre-Filter

When in use, pour water through the durable 40 x 40 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 filter into the centre of the filter, flip the bottle, and agitate the water until the Steripen indicates the treatment is complete.