Bitspower Artemis Manual AIR-Exhaust Fitting is our new series of air exhaust fittings, made from high-quality copper and manufactured with high-precision processes. There is typically an air chamber near the fill port of the reservoir. When the fill port is connected to this fitting, it ensures that the coolant will not overflow. Additionally, it allows for the release of air to regulate the pressure inside the air chamber, thereby maintaining the stability of the water cooling system. Model: BPM-ATETAIR-SL