In order to get the normal functioning of the ene, there must be a lot of clean air inhalation. If the harmful substances in the air (dust, resin, aluminum, iron acidification, etc.) is sucked in the ene, the cylinder, piston assembly will increase the burden, which will make them wear too much, so that the ene oil is interfuse, cause more substantial wear, lead to deterioration in ene performance and shorten ene life Air filter, like our nose, is the first "hurdle"of the air entering the ene, its role is to filter out sand in the air as well as some suspended particles to ensure that the ene is working properly, prevent ene wear. Meanwhile air filter also has a mute function Condition: Suitable for: Briggs & Stratton 491588 491588s 5043 5043D 399959 119-1909 colour:Blue + white Material:Plastic + filter paper size:13x11cm Package Contents: 10xAir filters for Briggs & Stratton In order to get the normal functioning of the ene, there must be a lot of clean air inhalation. If the harmful substances in the air (dust, resin, aluminum, iron acidification, etc.) is sucked in the ene, the cylinder, piston assembly will increase the burden, which will make them wear too much, so that the ene oil is interfuse, cause more substantial wear, lead to deterioration in ene performance and shorten ene life Air filter, like our nose, is the first "hurdle"of the air entering the ene, its role is to filter out sand in the air as well as some suspended particles to ensure that the ene is working properly, prevent ene wear. Meanwhile air filter also has a mute function Condition: Suitable for: Briggs & Stratton 491588 491588s 5043 5043D 399959 119-1909