Compression sacks work alongside that, squeezing bulky items such as sleeping bags and down jackets down to a smaller packed size. That extra space matters most on multi-day trips, where fitting everything in without overloading the pack becomes a real constraint rather than a convenience.
Used together, dry bags and compression sacks make it easier to organise a pack's main compartment, keep wet and dry kit separate, and protect anything that can't get wet at all. Shop drybags and compression sacks from Sea to Summit, Osprey and more at Cotswold Outdoor.