5tubes flow meter Technicial specification: O2, N2O, Air five tube O2 tube 0L/ min--1L/ min--10L/ min N2O tube 0L/ min--1L/ min--10L/ min Air tube 0L/ min--10L/ min O2 and N2O Linkage Device , adjust O2 and N2O in proportion( O2 concentration is not lower than 25% )