599-7785: Cab Air Filter Cat® Cab Air Filter, Plastic, L x W x T: 279 x 178 x 22mm Cab air filter such as 599-7785 is used in operator station duct and cab air filter group. Cat cab air filter such as 599-7785 is composed of cellulose based fiber paper cotton or other engineered material. The intended use of air filter is to protect cabin from particles in the air during the air flow. In design of air filters of cabin, maximum air consumption is taken as a basis. In order to determine the average air flow rate, It prevents bugs, leaves and other debris from clogging up the system. New