Hydronic Air Vent Automatic Float (F)NPT Connections (In.) 1/2 in (M)NPT Connection (In.) 3/4 in Connection 3/4 in (M)NPT or 1/2 in (F)NPT Overall Height (In.) - Max Temp (F) 250 Degrees F Max Pressure (PSI) 75 psi Material Brass and SS Construction Base Brass Forging Float Stainless Steel Pin Brass Seat Brass Shell Brass Stamping