A single nipple inlet and outlet aluminum cap with a captured VITON o-ring seal for your water bottle fuel tank!
Use the following to add a second pickup or a vent line to your tank:
Use this item for adding a second pickup to your fuel tank - Aluminum Pickup and Feed (Double Barb)
Use this item for adding a vent line to your fuel tank - Aluminum Vent - Single Barb
These caps work very well with Fiji Water bottles - or any similar Water/Soft Drink water bottle.
Here is a pic of the cap installed on a Fiji Water Bottle (The fitting on the top of the Fiji Water bottle is a Aluminum Vent - Single Barb listed above):