I use this when going out for a full day of warm weather riding on my Beta 430 RR-S. 3L seems to be plenty of water for me. Even 2.5L is good. The pack has enough additional storage space to hold a lunch, snack bars, iPhone 8+, sunglasses and my hat. The pack is not too big. Often, I forget that it’s even on. For me it is the perfect size for hard enduro riding. I found it to be great for all riding conditions and temperatures. Very well made and worth every cent.