The simple Source clip-top bladder is easily accessed via the full length zip pocket. Wrestling a full 1.5 litres can be a bit of a struggle, but once it's in there the pack's nice and stable on its airflow back pad, despite the lack of a waist strap.
Another full length gear pocket and an external bungee take care of stowage. There's not much give in the mesh shoulder straps though, and the two side pockets are pitifully small. The tactile hose coating is a nice touch that makes adjustments easy but the dangly bite valve cover drove us barmy until we chopped it off.