At 4 A, this breaker protects smaller loads — think control transformers, solenoid banks, or a single small motor — not a main feeder. The 15 kA (EN 60898) / 20 kA (IEC 60947-2) breaking capacity is well above typical panel fault levels for a 4 A branch; you're unlikely to exceed it in a standard distribution board. The 20 kA figure under IEC 60947-2 is the one to cite when the panel is built to that standard, common in industrial switchgear. Current derating is published: 4 A at 30 °C, 3.8 A at 40 °C, 3.6 A at 50 °C, 3.44 A at 60 °C.
Snap-on DIN rail mount, 4 modular width units (18 mm per unit). Any mounting position allowed. IP20 with connected conductors. Temperature range -40 to 75 °C covers cold storage and hot enclosures alike.