What the line is and how the seed part fits
The 1SAZ421201R1006: Procurement-wise it lives in the Contactors and Starters / Thermal Overload Heaters for Starters lane, which is the correct punch-out category for an indirect-spend tail buyer adding it to a starter BOM — no maverick SKU, no off-catalog line.
Spec recap and what's not on the slip
Single-supply part — no fieldbus, no auxiliary electronics inside the heater; the heater is a passive bi-metal element that the starter's mechanism reads. Communication to the starter is purely mechanical/thermal, so there is no protocol address to set on the unit itself. Mounting is onto the matching ABB starter frame under the contactor; it is not a DIN-rail standalone device. Verify the contactor frame matches the heater's intended starter before energising — a wrong-frame pair gives the wrong trip curve even when the heater physically seats.