referring now to the drawings , and more particularly to fig1 there is illustrated a fluid distribution system 10 including a container 12 with a spout assembly 14 . spout assembly 14 allows for the ingress of air into container 12 while fluid in the container passes therefrom . now additionally referring to fig2 and 3 , spout assembly 14 has a discharge passage 16 , an air ingress tube 18 , a one - way valve 20 and a cap 22 . discharge passageway 16 includes a corrugated portion 24 , non - corrugated portions 26 and 28 , a retaining feature 30 and a retained end 32 . discharge passage 16 allows fluid from container 12 to egress to a desired location chosen by the user . while the fluid is escaping a slight vacuum occurs within the container thereby causing air to flow through air ingress tube 18 , through one - way valve 20 and into the fluid . the air of course rises and joins the air already in container 12 . spout assembly 14 is configured to be attached to a jug or other pour container such as container 12 . it has been discovered that the length of air ingress tube 18 needs to be sufficiently long enough to allow the air passing therethrough to not enter the fluid flow stream going through portions discharge passage 16 . cap 22 covers the opening of container 12 with portion 28 and air ingress tube 18 connected to cap 22 . in the embodiment shown cap 22 is threaded to accommodate a threaded portion of container 12 . although other connection configurations are also contemplated . corrugated portion 24 allows for a robust flexibility of spout assembly 14 , while portions 26 and 28 are smooth and retain a certain resilient rigidity . cap 22 is configured such that portion 28 may be offset from the center of cap 22 , thereby allowing room for air ingress tube 18 to be part of spout assembly 14 . check valve 20 may be a simple check valve , such as a rubber duckbill valve effectively preventing the escape of fluid therethrough yet allowing air to pass therein . discharge passage 16 has a cross - sectional area that is larger than the cross - sectional area of air ingress tube 18 . this is in recognition that the fluid passing through discharge passage 16 is less compressible than air and that the air passing through air ingress tube 18 can move with less restriction in the flow . air ingress tube 18 as well as valve 20 are not connected to nor are they in contact with the container , except of course indirectly by way of cap 22 . rather air ingress tube 18 and valve 20 resiliently flexibly extend from cap 22 inside of container 12 and are generally substantially submerged in the fluid as it is poured from container 12 . of course as the level of the fluid drops portions of air ingress tube 18 and valve 20 may be exposed to air inside of container 12 . air inside of air ingress tube 18 provides some degree of buoyancy to tube 18 causing it to flex somewhat toward the surface of the fluid , which advantageously reduces the pressure difference needed for air to pass through valve 20 . air ingress tube 18 has a length that is greater than the diameter of discharge passage 16 . discharge passage 16 may be longer than air ingress tube 18 , with each extending on opposite sides of cap 22 . there is no limit on the length of ingress tube 18 , but generally a length that allows valve 20 to extend substantially into the fluid of a full normally positioned container is preferred . fig3 shows an expanded view of cap 22 . the present invention advantageously allows for the venting of an unvented container , such as a fuel container so that it can be easily retrofit to unvented containers and can be stored separately when not in use . retained end 32 can be routed back around and enter into a portion of portion 28 being secured by an indentation thereon shown as retaining feature 30 . this helps keep the interior of discharge passage 16 from being contaminated . if check valve 20 were to be located on or adjacent to cap 22 , since vent tube 18 only directs the flow of air away from the flow of fluid as it moves toward the spout , it would not vent very well . it has been found that the best venting occurs the farther into the container that check valve 20 is located . for example , consider the fluid in the container , at the very start of the pouring cycle . nothing has yet come out of the spout and there is no vacuum built up in the container . at this moment , the fluid head pressure helps seal check valve 20 closed . as fluid comes out the spout , the vacuum in the container increases to such a point that the ambient air pressure overcomes the fluid head pressure , opening check valve 20 , and allowing air to enter the container and lessen the vacuum . the less fluid head pressure on check valve 20 , the sooner the air in valve 20 overcomes the head pressure and allows the air into the container . now , additionally referring to fig4 - 6 there is shown another embodiment of a spout assembly , here for purposes of understanding , similar elements are numbered with 100 added to the reference numbers for similar parts introduced above . spout assembly 114 further includes tubular portions 150 , 152 and 154 with corrugate portions 156 and 158 connected therebetween . tubular portions 150 , 152 and 154 are substantially cylindrical in shape and each have a diameter with the diameter of tubular portion 150 being the largest and the diameter of tubular portion 154 being smaller that the diameter of tubular portion 150 to thereby allow tubular portion 154 to be inserted into tubular portion 150 , as shown in fig6 . further , tubular portion 152 has a diameter that is between that of tubular portions 150 and 154 . more specifically , the inner diameter of tubular portion 150 is larger than the outer diameter of tubular portion 154 . cap 122 has internal threads 160 which allow cap 122 to be secured to container 12 when tubular portion 154 is inserted into tubular portion 150 at least one of the corrugations of corrugated portion 158 contacts threads 160 , and even flexibly interferes with threads 160 . this interfering contact serves to help retain tubular portion 154 in tubular portion 150 . tubular portion 154 may additionally be longer that the length of tubular portion 150 allowing a distal end of tubular portion 154 to contact the inner portions of at least one corrugation of corrugated portion 156 , as shown in fig6 . this arrangement may additionally help retain tubular portion 154 in the position shown in fig6 . still further , the resiliency of spout assembly 114 is such that an angular force is applied between tubular portions 150 and 154 and this angular force coupled with the coefficient of friction therebetween also aids in the retention of tubular portion 154 inside of tubular portion 150 . while this invention has been described with respect to at least one embodiment , the present invention can be further modified within the spirit and scope of this disclosure . this application is therefore intended to cover any variations , uses , or adaptations of the invention using its general principles . further , this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims .