Designed to fit all MSR fuel pumps and liquid fuel stoves, the 20 oz capacity Medium Fuel Bottle is made from a single-piece of seamless extruded aluminum to prevent leaks and cracks. Its child-resistant safety lid requires a push-turn action to prevent young children from opening it, additionally the lid is air-tight to ensure that air will not enter the bottle and degrade the fuel. The shoulder and base are bolstered to prevent bulging when the bottle is filled and pressurized. This bottle ships empty and requires you to fill it with fuel.