The CamelBak Mule (2012 edition) could be the perfect activity bag. CamelBak’s are of course known for their water bladder and pipe system making it easy to drink on the go without having to stop, unpack and repack your bag. The Mule has a 3 litre bladder with all the features you would expect from a CamelBak - Quick Link™ System, 1/4 turn - easy open/close cap, lightweight fillport, dryer arms, center baffling and low-profile design, patented Big Bite™ Valve, HydroGuard™ technology, PureFlow™ tube, easy-to-clean wide-mouth opening. CamelBak say 3 Litres is enough for 3 or more hours of mountain bike action.
The Rucksack itself has a cargo capacity of 9.5 Litres packed with pockets and features -Media pocket, bike tool organizer pocket, stash pocket, four point compression, stretch overflow helmet storage. It’s designed to carry Helmet, multi-tool, pump, spare tube, extra layer, lunch, MP3, phone, wallet, keys - so pretty spacious whatever your use.