The T16-4.2 is a miniature auxiliary contact block designed for use with ABB's across-the-line contactors in AC and DC control applications. Based on the datasheet context, this product is part of ABB's auxiliary contact block family used to expand the switching capabilities of contactors such as the AF, A, AE, and AL series. The block is available in multiple termination styles including screw terminals and quick-connect (flat pin) configurations to accommodate various installation requirements. It integrates with standard contactor platforms to provide additional control circuit switching capacity for pilot duty and control applications. These auxiliary blocks are commonly used in motor control centers, industrial automation systems, and electrical distribution equipment where expanded contact configurations are required beyond the standard contactor offerings.