Holds a 1L bottle upside down, primarily for the purposes of a Brine Shrimp Hatchery. Perfect for breeder aquariums and for raising fry. For this purpose you'll also need a "Co2 bottle cap" for 1L/2L bottles - you can get these for <$1/ea. on eBay if you don't mind the wait.

Designed specifically around a 1L Coke bottle, but I suspect most brands should fit fine. The top hole is 90mm so there is a little bit of play allowed. The pegs are 7.75mm wide and the holes for them at 8mm wide. This offered a perfect press fit for me, but I'm actually overextruding a bit right now so I have provided the Fusion 360 file if someone needs it to tighten those tolerances.

For proper assembly, you will need:

• Printed parts
  • (1) 1xMiddle.stl - this is the piece the neck of the bottle rests on
  • (2) 2xTopBottom.stl - this piece is repurposed as both the top and the bottom
  • (4) 4xArmLong.stl - these arms go between the top and the middle
  • (4) 4xArmShort.stl - these arms go between the middle and the bottom
• (1) Co2 Bottle Cap for 1L/2L bottles
• Airline tubing
  • (1) Short piece, approx 6" or as desired
  • (1) Long piece, approx 18" or as desired
• (1) Microball valve

TheKingofDIY has a great video on setting up and using your Brine Shrimp Hatchery here.

I intend to attach more pictures of the assembled hatchery later :P.