SealLine'slightest waterproof protection, Cirrus Sack dry sacks are perfect for minimalists seeking essential protection with the least possible weight. They're built with an ultralight, silicone impregnated nylon, fully taped seams and a water shielding roll down closure for maximum protection. Large sizes make great pack liners for rainy backpacks, and smaller ones create welcome havens of organization and protection on any journey. Ultralight Protection: SealLine's lightest and most compact dry sack for trips where every gram counts. Waterproof Protection: Sewn and taped, silicone coated 20D nylon. Secure Closure: Roll top closure creates a secure seal. PVC Free: Eco friendlier coatings reduce environmental impact.