i got a berghaus cubic 25, it's sized on such a fashion that you it will fit a A4 binder in it easily, has a 2L hydrationbladder sleave, one main pocket, one smaller pocket in front with some small sleaves for small items. on front and on one side there is a mess pocket. The side mess pocket is very usefull to put your bottle in, readily accesaible and it doesn't attract weardo looks, like wenn i carried a hydration system... it also has a cellphone pocket on the straps, wiht a small hole under it for handsfree phone kits ( i don't have a phone... ). it has kept mine books dry, but you it does feel a bit damp on the inside after it has been in the rain. The waist band is a bit thin and i would have liked more pockets, but in general, i like it.
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