The CAT 1W-8922 (1W8922) is a piston ring kit designed for Caterpillar 3400 series diesel engines, including 3406, 3406B, 3406C, 3406E, 3408, and 3412 models. It is used to seal the combustion chamber, transfer heat, and manage oil consumption in heavy-duty equipment like articulated trucks, bulldozers, and mining machinery