Osprey Mira 18

Backcountry.com says:
Light and lean but generously equipped like its larger siblings, the Osprey Women's Mira 18 Hydration Pack carries your goodies, gear, and hydration for a day in the wild in a supportive, well-balanced, and ventilated system. Women-specific shoulder straps, hip-belt, and torso sizing provide a precise, uncompromising fit and enduring comfort. Plentiful pockets and organizing features keep everything tidy and conveniently accessible.