The DTF (R) series axial fan has 14 fan sizes 12.5#、14#、15#、16#、18#、19#、20#、21#、22#、23#、24#、25#、26#、28# , also different blade number 10,12,14,16 and different speeds total 24 models.air flow ranging from 35,000 to 750,000 m3/h, air pressure from 300 to 2,000 Pa.