The ABB TA75DU42-20 is a thermal overload heater element for motor starters, with a setting range of 29-42 A. It is the current-production thermal element sized for that amp window — the part that clips into the overload relay base and tracks the motor's thermal load through a bimetal strip. If you are replacing a failed heater or building a starter from a loose contactor and overload block, this is the ABB order code for the 29-42 A range.
What the 29-42 A setting range means for fit
The 29-42 A range is the trip-current window the heater element is calibrated for. That means the full-load motor current (FLA) must fall inside that band — you select the heater so the motor's nameplate FLA sits somewhere between 29 and 42 A, and then you dial the overload relay's adjustment knob to match. A 30 A motor lands near the bottom of the range; a 40 A motor lands near the top. If your motor draws 25 A or 45 A, this heater is the wrong size — step up or down to the adjacent TA75DU heater code.