The Siemens 3RB1026-2NB0 is an electronic overload relay rated for 0.4 to 1.6 A, with a class 20 trip curve. It uses screw terminals and mounts directly to a contactor in the size S0 footprint.
The 0.4 to 1.6 A adjustment range covers fractional-horsepower motors and small pumps, fans, or conveyors on a 400 V or 480 V line. Class 20 means it allows up to 20 seconds at 600% of the set current before tripping — that is the standard curve for standard-start induction motors; it handles the inrush without nuisance trips on a typical pump start. The screw connection is a straightforward field-wiring choice: strip, torque, and go, no special tooling needed.