The 'old' canteen has been the godfather here. Lightweight and stable. Adapts very well thanks to the kidney shape and is really leakproof. Can e.g. be attached to the backpack or daypack by carabiner. Big enough for 1 liter but small enough to be well transportable. Available in different colours: blue, coyote, foliage, grey and red.
lightweight and compact
leakproof and unbreakable