P171537 Synthetic, Efficiency Beta 1000:
11 micron
P171539 Cellulose, Efficiency Beta 2
10: micron, Efficiency Beta 200:
32 micron, Efficiency Beta 1000:
36 micron
P171540 Cellulose, Efficiency Beta 2:
27 micron
P171541 Wire Mesh, Efficiency Beta 2:
60 micron
