Keep your engine clean and protected with Castrol Foam Air Filter Oil. This filter oil has been specially formulated for use with wet type foam air filters that are commonly fitted to many 2 stroke and 4 stroke engines. Designed using a balance of carefully selected base oils and additives, Castrol Foam Air Filter Oil will trap dirt and other abrasive material and stop it entering your engines intake that can cause major damage to engine internals. The aerosol application makes application simple, quick and with minimal mess so you can get back on your bike sooner.