There was a change to the air filter design. American Air Filter Company later built premises. Koch is the founder and owner of FilterTime, a residential air filter delivery service. They have a unique cartridge-like organ that serves as an air filter. The crew is supplied clean air via an air filter system. Air filter purification traps airborne particles by size exclusion. The airbox allows the use of one air filter instead of multiples, reducing complexity. The Metropolitan even encouraged beards for staff to act as an air filter. R3 Division also used an R3 Carbon Fibre Air Intake with K&N Air Filter System. Some of these filters are rectangular and similar in shape to the combustion air filter. Larger head pipes and larger mufflers with a less restrictive air filter all improve response. Examples thereof are&colon; was the alternator fitted?; was the air filter fitted? In 2004, all models were fitted with a cabin air filter. Another cause of failure is a faulty air filter. The 2014 model has a wet-sump engine and an easy access air filter.