The Granite Gear Air Bag packing system helps you stay organized without adding a lot of extra weight. The new bloc shape makes them perfect for stacking inside your pack. The Bloc shape is their innovation to help you pack more efficiently inside your pack. Compared to a round shape, the bloc fits better into the corners of your pack, they stack nicely, and eliminate all the dead air that can happen when you try to pack with round stuffsacks. Less dead air means better load stability, quicker pack loading, and the possibility of carrying the same amount of gear in a smaller pack, saving you weight. Assorted colors.