A perfect way to bring a clean outfit if you're running to work! Since it only comes in grey, your colour choice is made very easy and it holds one litre.
From Amazon
CAMELBAK Womens Hydrobak 2.5 Litre Hydration Backpack with 1.5 Litre Reservoir - Drizzle Grey/Silver Cloud - 2.5 Litre/1.5 Litre
ePacks
Camelbak Women's Hydrobak Light Hydration Pack