The 1.5SMC27A M6G: This makes it a fit for 24V DC rails (nominal 24V with tolerance) where the protection window between working voltage and clamp is tight.
Package and board integration — DO-214AB (SMC) footprint
The copper pad area under the cathode tab sets the thermal resistance to ambient — for a 1500W pulse, the board's copper plane acts as the heat sink, so a larger pad on the cathode side improves surge repetition capability. The wide range means derating at high ambient is minimal for single-shot surges; repetitive pulsing needs thermal analysis based on the PCB layout.
The 1.5SMC series is a common TVS footprint, so cross-shopping with other brands (Littelfuse, Vishay, ST) for a second-source hedge is straightforward if the BOM volume justifies it.