This is a remix of mcfada's One Gallon Milk Jug Cap.
I use a 1 gallon milk jug to transfer bird seed into the feeder in the back yard. I purchase seed in 10lb+ bags which are combersome to try to fill the feeders. I am using this union to mate a undisturbed gallon milk jug with one with the bottom cut out that I use as a large funnel. This makes pouring the seed from the 10lb bag into the milk jug much easier. The 1 Gallon milk jug will fill my feeder a few times before I need to refill it again.