Abstract: A foldable bag material is formed into a bag having at least one end with a corner and having an end closure formed by the bag material which closes off the one end of the bag. A filter valve tube extends within the end closure at the one corner, the tube having an inner end disposed within the interior of the bag such that the tube is adapted to receive a filler nozzle of a pneumatic filling device for filling the bag with a filling material. The tube has an inner end portion and an outer end portion, the inner end portion having a cross-sectional contraction which is contracted relative to the outer end portion such that the contracted inner end portion forms a seal with the filler nozzle, the tube being made at least partially of a filter material which is gas-permeable but which retains the filling material such that the gas-permeable material provides for venting of the bag during filling.