MIP Connection Automatic Air Vent for Hydronic Heating Applications 1/8", Everflow, Mfr#: AV-T18$22.89+
Hydronic Air Vent, Automatic Float, (M)NPT Connection 3/4 in, (F)NPT Connection 1/2 in, 75 PSI, Bell & Gossett, Mfr#: 79$200.99+