I just reuse a volvic bottle. Only 50p and i can use again and again, saving money aswell as saving the environment at the same time. The bottle is enough to keep me going till i get back to the office. I don't mind wasting 5 seconds of my time getting the bottle out of the bag twisting the cap and taking a sip
If i drunk more than a litre or two i would be p*****g myself.
Hydration packs are good for storing items such as keys, but RM would never supply us with one, as it would probably blow their profits out of the water!