The ABB A16L-40L-00-84 is a mechanically held contactor from the A16 series, described as a tungsten-rated, mechanically held device. Mechanically held contactors latch in the closed position without continuous coil power, which means they hold their state through a power interruption — useful for lighting or heating loads where you don't want the circuit to drop out on a momentary brownout.
The description — "A16 Tungsten W/l" and "MECH HELD" — flags that this contactor is built for tungsten lamp loads, which have a high inrush current when the filament is cold. The mechanically held (latching) feature means the main contacts stay closed after the coil pulse drops, so the tungsten inrush is handled once at the initial close, not repeated on every power cycle. That's the design intent: a lighting contactor for large banks of tungsten or resistive loads where latching is preferred over electrically held.