Stainless steel cowl-mounted air cleaners and caps are available on Peterbilt Models 389, 388 and 367, in both 13-in. and 15-in. diameters for single or dual side installations. Developed by PACCAR, the air cleaner uses nanotechnology to trap submicron contaminants, extend maintenance intervals and prolong engine life, the company says. The air cleaner features a new air filter seal.