What it is and where it fits
The Square D SSM1A445F7 is a solid state overload relay, sitting in the Circuit Breakers, Fuses & Protection category under Relays and Solid State Overload Relays. It's the component that sits between the contactor and the motor, monitoring current and tripping on overload — no moving parts to wear out, so it's a fit-and-forget piece in a motor control center or standalone starter.