On the other hand, if the filtration is intended to remove smaller particle sizes, i.e. in the diameter range <0.3 µm, decreased filter area does cause a decrease in filter efficiency. The diagram below compares filtration efficiency data for two compact filter types, MPK 412-31 GT (effective filter area 25.3 m²) and MPK 412-38 GT (effective filter area 30.5 m²), both classified as E12