Sea To Summit eVent Compression Dry Sack - The eVent Compression Dry Sack from Sea to Summit is a completely new concept in compression dry bags - there is no valve! This innovation uses an air-permeable base made of eVent waterproof fabric, which allows air to be pushed out of the sack, but wont allow water to get back in. Suitable to keep contents dry in any wet situation where the bag is not submerged. The roll top Hypalon closure with lid and 4 straps evenly compresses and maintains compressed size to save you space. Meet the compression dry sack of the future, the eVent Compression Dry Sack from Sea to Summit!