SPACE SAVER COMPRESSION BAGS:

These easy to use space-saver compression bags dramatically increase your packing space.
Simply fill the bag with your gear through the zipped opening, seal the bag at the zipped opening using the included plastic slider,
and then roll the bag to remove the air though the one-way valve. Please even see below illustrations.
Includes one Large bag (51x71cm) two Medium bags (41x61cm) and one Small bag (36x51cm).
The bags are reusable and increase your packing space by up to 70%.
They can even be used for compact storage at home!