G'day Dan,

The pre-filter is a separate attachment that will attach to a wide mouth water bottle (most Nalgene or Camelbak models). You screw it on with the filter cartridge in place, fill the bottle from the water source, then remove the cartridge and insert the pen into the slot the cartridge usually seats in. It would be with having a look at the downloadable user guide at the bottom of the specs section for a diagram of this.

G'day Cameron,

The temperature will impact how quickly batteries will discharge, so depending on the batteries you've used and the temperature it is likely that this is why you had some issues. Lithium batteries will last the longest in colder weather, so if you give the unit a whirl with those is colder weather you should see a better battery life.

G'day Jessie,

The SteriPen is designed to treat either 500ml or 1L of water using a specific timeframe to effectively kill any bugs. A Camelbak is generally a 2L or 3L bladder which potentially could mean the water is not effectively sterilised and given that this is fairly critical we wouldn't recommend this as a safe option.