Bought the Sawer in-line filter from Sportsman's Warehouse for $39.99 and the Platypus adapter from REI for $3.95.  
It fits nicely in my CamelBak, Blowfish, PSK. The water flows  by gravity.  The filter has a very long shelf life and it is good for 500 gallons.  It filters out all the bad bacteria.  I wish Doug would review this filter.  <img src="/images/graemlins/wink.gif" alt="" /> 
 
   
 Learned that a pine dowel and a cedar board work together to make a coal using fire by friction (fire bow) .