1.Mounting cup : Aluminum ,20mm 2. Stem :2*0.51mm3. Inner Gasker : Butyl 4.NO2 ,N2 CO2 Available 20mm metering valveWe supply all kinds of metering valve and continuous valve1.stem:plastic,metal2.dosage:25ul,50ul,75ul,100ul3.actuator:L-actuator,round actuator4.mounting cup:tinplate with transparent coating 20mm metering valve