The 0.3 A rating is unusually low for a 2-pole MCB; this part protects a specific low-current DC circuit — think auxiliary control loops, signaling supplies, or battery-monitoring branches in a rail vehicle. Vibration resistance per IEC 60068-2-6 (±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz) matches the mechanical shock profile of traction and under-car equipment.
Fastens via the quick-assembly system; mountable in any position. IP20 with connected conductors, so it is intended for a protected enclosure, not open-rack. Sealable terminals and halogen-free / silicon-free construction are specified.