Universal sinus rinse adaptor (screw on soda bottle) - Nasal rinse, Neti Pot, Nasendusche

This modified universal bottle cap can turn any bottle into a sinus rinse container. It uses the standard 'PCO 1881' threading as used in normal soda bottles like Coca Cola.

The only thing you need on the bottle is a ventilation hole at the bottom of the bottle to control the speed and stop flow by plugging it with your finger.

The cap can be printed without supports, since the bottom is bridged with one layer, which needs to be removed after printing (drill or knife - easily accessible fr