Oil Breathers 3524146 allow ventilation of the crankcase, removing combustion bypass gases. These gases contain oil vapors, and the breather filter traps the oil and contaminants. For recommended changing interval see the Operation and Maintenance Manual Compatibility: 1200 Series: 1204E-E44TA, 1204E-E44TTA, 1204F-E44TA, 1204F-E44TTA, 1206E-E66TA, 1206E-E70TTA, 1206F-E66TA, 1206F-E70TA, 1206F-E70TTA