42 mm Filter Cap Picante quick drying Matrix Aero stretch Size:29 29 quick drying Matrix Aero stretch fabric with a Flexile 100 stretch waistband which is why we've integrated a high cut inner boot construction as well as a snug Sport Fit designed for athletic skiers The new 42MM Filter Cap threads seamlessly onto all sizes of HydraPak's 42MM thread Seeker water storage bags and Flux flexible bottles morphing them into filtration solutions The end result being lightweight filtration kits that can either be used to squeeze filtered potable water into other camp bottles and containers or to drink freshly filtered water from a Seeker or Flux