What the line is
The 1SBL137201R1300: It is a panel-board contactor — the kind that drops into a DIN-rail compartment next to a motor-protection breaker and a control relay. Nothing on the order code line reads as a coil suffix or an auxiliary count, so specifying it into a starter assembly means confirming the coil voltage and the auxiliary-contact block separately against the line drawing before the BOM is released.