Turn a water bottle into a bird-feeder.Outer ring is almost 16cm in diameter, so position it carefully!Print bottom and top. Hot-glue the two together.Screw a water bottle full of birdseed into it and hang with a bit of wire.NOTE: This thing is for 30mm bottle tops. If your bottle has 120 degree spaced thread starts.. print the _120 bottom STL. If it has an even number of thread starts, print the other bottom.(I may add a printed hanger in the future)