Keeps ’em dry and packs in perfectly. The eVent Sil Compression Drysacks by Granite Gear is one of those extremely useful items that everyone should have before braving the elements. It keeps items dry as well as compresses them to save space. Its block design amazingly compacts perfectly in any pack, and at somewhere between 2.8 and 3.8 ounces, it adds virtually no extra weight too. Who thought that a compression dry sack could be improved on, but the designers at Granite Gear definitely did it.