Thanks ayala_Jessica for the advice.
But I believe we cannot put alot of things inside Halzan as the strap will be stressed? Although I don't put a lot of things when I'm using for work or weekends.However,I'm more concerned when I travel as I will put a water bottle inside my travel bag.
I stuff mine quite a lot and it actually holds well and is roomier than I expected. If you wear it cross body you don't feel the weight and I don't think it stresses the strap. I have mine used almost daily since 7 months and no sign of wear. However I would not advise to put a bottle in it.