HydraPak have produced a number of accessories to fit their wide neck bladders and bottles. Three Points of the Compass has a glance at two of these, that permit a 28mm threaded water filter to be fitted.
In the first of two posts, Three Points of the Compass looks at two ways to fit a 28mm thread Sawyer Squeeze water filter to a 42mm neck HydraPak water bladder.
Three Points of the Compass 