Im buying this along with the Xpac duffel, it design to be sit in either side of errant duffel, secured by the duffle’s fidlock buckle and optional 2 metal hook from the pouch
The inside of the pouch only have one large room without partial compartment whatsoever. For the waterproof function, the pouch itself secured the load with velcro, adding the rollup mechanism and 2 small fidlock buckle.
It is waterproof, have big capacity, Good quality product overall, but it does not fit and look good when you are not fully load this pouch,
almost forgot, there is a standalone carry option with included strap too.