This float is for a tube with an inner diameter of 8 mm. I use it to check whether my water stack is full or not. It is a watertight box with an inlet, an outlet and a reed float contact. There are gaskets for inlet and reed contact. The bottom with the outlet is glued with white wood glue.
To improve waterproof quality the layer height is set to 0,15 mm and the seams are random. Printed in PETG.
 

This reed contact is used:

https://www.hobbyelectronica.nl/product/water-level-switch/?gclid=EAIaIQobChMIwbjVg5ni-QIVA4bVCh0QWwsEEAQYAiABEgKVFvD_BwE