This sack doesn't take much room in your kit and makes inflating your Thermarest mat a much faster process. Please note it is not compatible with classic valves (pre 2020 mats) but fits onto the newer WingLock and TwinLock valves. Designed in tandem with the folks at Sealline the sack has welded seams to keep 20 litres of gear dry when you're not inflating your mat. Weighs 150g and measures 26 x 61 x 14cm open.