... Demand5Laser Gas Mixturesbalance gas :HeH2,N2,CO2,Kr,F,CO,HCL,Constituent content As Demand6Welding shielding gas mixturesbalance gas :He or Ar,N2CO2,H2,O2,N2,He ... ,CH4,Ar,Constituent content As Demand7Keep fresh gas mixtures N2,CO2,O2,Constituent content ...