I looked around for a hydrometer mount plug for the cereal boxes used, there were a few, but in end decided just to design my own.
These ‘plugs’ allow the round hydrometer to be mounted.
The hydrometer is a tight fit, but not too tight. The plug is also the same.
Link to hydrometers used: https://www.amazon.co.uk/dp/B07HK22QB2
Printer: Bambu P1S
Nozzle: 0.4
Layer: 0.2
Infill: 15% - Gyroid
Filament: Sunlu PLA+ 2.0
Supports: None
The author marked this model as their own original creation.