Out Travel Storage Bag creates up to 75% more space in your backpack/luggage. Fill it with clothes, roll it up to force the air out, and viola! Your clothes take up much less space. No vacuum needed like the bags you may have seen on TV. Also provides a complete moisture barrier -- waterproofs your clothes. Also seals odors in -- important if you fill it with dirty clothes you've been wearing for a week. One year manufacturer's guarantee. An essential for those with the world on their backs. Medium: 19 x 13 inches.