The TM-D trip unit gives you fixed thermal overload and magnetic short-circuit protection — no adjustment dials, which means the trip curve is set at the factory and stays consistent across a multi-unit distribution board. Breaking capacity hits 50 kA Icu at 240 V AC and still holds 25 kA at 400 V AC, so it clears high-fault currents without cascading upstream in a 400 V distribution panel.
The 300 kA integral instant protection (I²t let-through limiting) is the internal energy-limiting capability, not a breaking capacity. For selectivity you'd need a Category B breaker upstream. The fixed long-time pickup at 1 In and fixed delay means the thermal curve is non-adjustable — coordination studies should use the published TM-D curve from the Schneider documentation.