Nathan Vapor Swift 4L

This light weight, pack utilizes the AdaptiveFit™ system to conform to the runner! The VaporAir’s little brother has a game changing fit and contours to your form, regardless of change to your shape or size. With the lightweight, breathable and chafe-free material, you can rest assured that when you gear up for your next marathon, trail run, hike or Spartan Race, you have all the hydration and storage for on the go that you need.