Class and panel role
The 1SAM451000R1015: Parts in the Contactor & Starter Accessories & Parts class are specified into the BOM to complete a starter assembly: they carry the electrical or mechanical interface between the breaker/contactor body and the panel wiring, and they share the accessory footprint rather than the main contactor frame. For the panel builder that means DIN-rail pitch, terminal style, and accessory bay geometry are the parameters that decide fit — not the contactor's main pole rating.