The M04040 Key is an essential locking component for King packaging machinery, designed to secure rotating parts, such as gears and pulleys, onto shafts. This durable key prevents slippage, ensuring stable alignment and efficient power transmission, which is critical for smooth operation in tablet counting, liquid filling, cotton inserting, labelling, and capping machines. Built to endure high-demand environments, the M04040 Key enhances machine reliability, supports consistent performance, and contributes to the long-term durability of King packaging equipment.