With a load capacity of nearly 10 litres (the same as a CamelBak MULE), this pack will fit most of your 'regular' ride stuff in it no problem, which is why it is our choice for the majority of rides, from quick blasts to half day rides. If you want a hydration bladder for this bag, most will fit, but if you need/want a new one especially for it we recommend the 1.5 litre Hydrapak reservoir, as it fits in very neatly. The 2 side pockets each have a (waterproof) zipped and a mesh compartment, both of which are easily accessible without taking the pack off - a really useful benefit when riding as they hold a fair bit of stuff such as a phone, tools and trail food.