Seamand 3L Hydration System Water Bladder Capacity:3L, For replacement only.Please refer to our hydration backpack from"seamand store" Five color to choose:Army Green, Khaki, Grey, Beige,Black. Army Green color used in Digital Camo, Woodland and Army Green bag, Khaki always used in CP Camo and Khaki bag, Grey used in ACU Camo bag. Beige used in Desert Camo and Digital Desert bag,Black color used in Black bag. If you want to buy hydration back with bladder please search in our store"seamand store" If you want to buy bladder only,please choose the color, If you don't know which color to choose, please feel free to contact with us.