The ATD03 BelAir float drain is most commonly used on the inside of their FT series of inline compressed air filters. The internal float rises when the moisture builds up at the bottom of the filter housing which drains the moisture out automatically.
The drain sits at the bottom of the filter housing and is secured to the housing via a nut on the outside of the filter.
This is an OEM part manufactured by BelAir
Also Known as Part Number ATD-30