The Watershed Westwater is a gargantuan dry backpack, the largest Watershed offers, with enough storage space for a multiday trip. Watershed engineers the premier dry bag on the market. Their ZipDry Seal technology can boast of an unprecedented, airtight seal that is guaranteed to keep gear dry even in the most extreme whitewater scenarios. All Watershed seams are radio frequency welded, a method, which has been proven to create a powerful hermetic seal. Constructed with 420-denier fabric with a heavy matte polyurethane finish for abrasion resistance and overall durability.