46.51.00 Air and Gas Diffusion Equipment
46.51.26 Shear Box Diffusers
46.51.11 Fixed Mechanical Aerators 46.51.13 Floating Mechanical Aerators 46.51.16 Submersible Aspirating Aerator Equipment 46.51.17 Jet Aeration Equipment 46.51.21 Coarse Bubble Diffusers 46.51.23 Swing-type Channel Aeration Equipment 46.51.26 Shear Box Diffusers 46.51.31 Flexible Membrane Tube Diffusers 46.51.33 Flexible Membrane Disc Diffusers 46.51.36 Ceramic Disc Fine Bubble Diffusers 46.51.43 Floating Membrane Diffusers 46.51.46 Membrane Diffusers 46.51.53 Cascading Aerators 46.51.63 Pure-oxygen Generating Equipment