A

Used to protect organic gases or vapors with a boiling point greater than 65°C, such as benzene, carbon tetrachloride, nitrobenzene, cyclohexane, etc.;

brown

B

Used to protect against inorganic gases or vapors, such as cyanogen chloride, hydrocyanic acid, chlorine, etc.;

grey

AND

Used to protect against sulfur dioxide and other acidic gases or vapors;

yellow

K

For protection against ammonia and its organic derivatives;

green

Filtration efficiency 1%

≥99.97

≥95.0

≥90.0