What it is on the BOM
The 1SAZ711201R1035: It is the electronic-trip sibling of a thermal overload relay — same panel footprint family, different sensing element — which is the line on a spec that decides whether a retrofit swap requires re-derating the motor branch.
Where the class is applied
Solid state overload relays in this ABB series are specified into motor-starter compartments where the controlled load is a three-phase induction or servo-driven machine and the panel builder needs a settable, repeatable trip curve instead of a fixed thermal element. On a packaging-machinery BOM the 3-pole format mounts directly under the matching ABB contactor frame and accepts the same line/load conductor routing, so it drops into the starter module without adding a DIN-rail accessory.