Exped ventair compression granite grey bag size m 19 ltr product description the exped ventair compression bag is an excellent waterproof bag for keeping your possessions on to protect them against water dirt etc the exped ventair compression bag features four compressions straps that run vertically down the bag and which allow the air in the bag to be expelled to give the smallest possible bag size but also to concentrate the contents into a solid load that is much more comfortable to