The A9N4P40BIN is a 4-pole miniature circuit-breaker from the Acti9 range, rated at 40 A with a B tripping curve. Breaking capacity is 10 kA at 380–415 V AC, 50/60 Hz, per IS/IEC 60947-2. That's enough for most secondary distribution panels where the fault level at the board doesn't exceed 10 kA. The 4-pole construction switches all phases plus neutral, so it's a straight fit for three-phase four-wire systems where you want the neutral opened and isolated alongside the phases.
Occupies 8 x 9 mm pitches (72 mm wide). The bottom terminals are biconnect type, which means you can land a cable and a busbar in the same clamp without doubling up on lugs. IP20 finger-safe protection on the front; pollution degree 3 rated, so it's fine in panels that aren't sealed clean-room tight.
Designed and tested to IS/IEC 60947-2 for low-voltage switchgear and controlgear. Utilisation category A (no intentional short-time delay). Suitable for isolation per the same standard — the ON/OFF toggle gives a visible break. Overvoltage category IV, so it's rated for the mains entry point in a building installation, not just downstream sub-panels.