The A16L-40-00-84 is a 4-pole lighting contactor with a mechanical latch, controlled by a 120V coil. The latch holds the contacts closed without continuous coil power, so it's used in lighting panels where you want maintained switching — the coil pulses to latch or unlatch, then drops out. That saves coil power and eliminates hum, but it also means the contactor stays closed through a brief power dip, which matters for emergency lighting circuits that must stay on.
This is a panel-mount contactor sized for lighting control — think commercial or industrial lighting contactor cabinets, emergency lighting transfer, or any circuit where a mechanically latched contactor provides maintained switching without continuous coil draw. The 4-pole configuration handles three-phase plus neutral or four independent lighting circuits. The mechanical latch means the coil only draws current during the switching transition, so the contactor stays in position through a control-power interruption.