The topeak mondopack hydro is another great wedge bag from their new range although the hydro is the same basic design as the mondopak xl it features an external pocket in place of the expendable main compartment this is a very useful feature which enables you to easily carry extra water for extended trips or it could be used to store a lightweight jacket topeak mondopack hydro wedge bag features 32x13x20cm capacity 17 litre105ci 312g