examples: https://www.ortlieb.com/en/fototasche/


Pelican cases http://www.pelican.com/us/en/ not only water tight but some are Airtight
and so have a Pressure equalization valve
so if you try to open them at a lower altitude than the last time, the air pressure difference wont work against you.

If you Justify that front rack You can make a Mount for it.

Ortlieb handlebar bar bags are showerproof , with water coming from above , But In a Flood-Stream crossing & your bike falls in,
Otherwise , immersion, it will let water in.



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