Ran the Cumberland Trail 50K today (more on that ASAP) and wore my new Nathan Trail Mix 4 bottle pack.
This is by far the most comfortable unit I have ever strapped on. The elastic waist belt is fully adjustable and rides snug but not tight. On several occasions, I actually forgot I had it on.
Weight distribution is excellent among the four (4) 10 ounce nutrition flasks.
Storage pack is small but ample for most needs.
This is one hot unit and I want to give Nathan a shout out for a fully functional design.