Covers for hydration bladders are practical in the sense that you can take a drink with you even if you are traveling light and do not intend to take a full-sized backpack. They are usually so low-profile that when carrying them, you'll feel as if you aren't carrying any baggage at all. Basically, you can choose between two options: a cover for attachment to the MOLLE system and a cover with classic straps like a regular backpack.

Both options come with their own advantages, so the choice is yours. The straps can often be removed, and the cover can then be inserted into a larger backpack. Thanks to the internal padding, the hydration bladder will be doubly protected and also better insulated from the external environment and its temperature. There are also covers that combine the advantages of both solutions, meaning you can choose whether to carry them on your back with classic straps or attach them to, for example, a tactical vest.

The MOLLE/PALS webbing is often also found on the exterior of covers and pouches for hydration bladders, so you can attach additional storage space and other tactical gear to them. With some models, you can also fasten additional equipment onto drawstring loops on the front panel—this could be a raincoat or sleeping mat, for example.

Compared to other backpacks, covers for hydration bladders are usually equipped with a drainage hole at the bottom. This is in case the contents of the bladder accidentally spill out. Excess water simply drains through this hole; you let the cover dry, and it can be used again.