A Camelbak is no different than a normal backpack, except that you can fill it with water / electrolyte drink. The main weight is the water, but you feel it less than waterbottles in jersey pockets, because the weight is distributed. I have 3 Camelbaks, Rogue (small-shown in photo), Lobo (medium) and Mule (large). I use the Rogue 90% of the time and it can hold the equivalent of 3 large 24 oz water bottles, which is sufficient for a 50 mile non-stop ride. I carry a mini-pump, spare tubular tire, 3Wrencho, wallet, cell phone and house keys.