Primary air filter for Perkins engines 26510342 are designed for normal duty diesel engine filtration applications to remove particulates and meet strict standards to provide the best value protection for your Perkins engine. Fin diameter 130mm. You can’t control the environment you’re working in, but you can keep your engine working longer by keeping the air used for combustion clean. Removing particulates prevents wear to vital components such as injectors and turbochargers.