Works Great!
"I’m using this raincover (size: M 25-35L) with my Mammut Nirvana 30. As expected, it fits a bit loose but the extra room is appreciated when strapping my Ducan Light HS Hooded Jacket on the outside of my backpack. The elastic cross-strap has a small profile and does a sufficient job of keeping the raincover secure in windy conditions without adding extra bulk."