Use HPI Engine Air Filter Oil to properly maintain your nitro engine - just a few drops after cleaning your air filter will keep it in top shape and ready to protect your engine from dangerous dust and dirt particles. Also available is HPI After Run Oil for nitro car and truck engines, plus 2-Stroke One Shot Engine Oil for petrol 2-stroke engines. #101909 HPI Engine After Run Oil (50ml) [10/Carton] #101910 HPI Engine Air Filter Oil (50ml) [10/Carton] #101911 HPI 2-Stroke One Shot Engine Oil (200ml)