These fully tested waterproof stuff bags have a roll top closure which also acts as a compression system squeezing air out of the bag as you roll down 7 sizes and a multipack are available and each size is colour coded ideal for using inside or outside a rucksack or as a full rucksack liner9679 30 denier siliconised cordura9679 fully taped seams9679 roll top closure with single click shut buckle9679 this item is on the dofe recommended kit list