I use the Camelbak racebak on longer training days and some races. The vest that holds the bladder goes under your race jersey. It stays in a great position and it never becomes an issue. It can hold up to 2 litres of my go to hydration mix Alete, its a natural product that has everything you need and nothing you don't. The bladder comes with a long pipe that I have been meaning to to shorten so the mouth piece is in a better place for me. Great product to have in the tool kit for the training day or race that suits it.