I use this product with my Salomon Lab 5 Vest. For longer runs in hotter weather I take out the water bladder from the vest and I use two of these bottle that are placed up front. With that, I''m able to see how much water I''m drinking and it''s quicker for me to refuel up the flasks at the random aid stations during endurance runs. Also a good thing is, the flasks collapse as you drink out of them, so you don''t have that dead space that causes all the movement as it does in regular water bottles. Only two things I would like to change is a stronger material and a cheaper price for them rubber flasks. Other than that, it''s well worth it.