Forms a block shape when compressed that fits perfectly in your pack * Designed to be used inside your pack and not as a drybag or haulbag * Arched rolling stay keeps Bloc open while loading/unloading and forms an easy to grab handle when sealed * Medium: 5.7oz; Large: 7oz; X-Large: 7.4oz * Medium: 50-65L; Large: 65-90L; X-Large: 98-120L