Hard alloy metal powders are widely used in many industries applications.Quality control on fisher number of hard alloy metal powders are important.As we know hard alloy is difficult to be measured by laser diffraction method due to high density and difficulty in suspending. So far air permeability testing method is a most popular and effective sizing technique for hard alloy metal powders.It gives average particle size calculated from specific surface area being measured.The first company using such method is Fisher Scientific unfortunately it's typical model Fisher 95 sub sieve sizer was discontinued.AimSizer is a China company with years of experience in fisher sizing and the HMK-22 Fisher sub sieve sizer has become the best successor of Fisher Model 95.We convince hundreds of users worldwide.(To be continue)