That D curve means it's designed for loads with a high inrush current — think motor starters, transformers, or welding equipment — where the magnetic trip won't nuisance-trip on startup but still clears a hard short. It's rated for 400 V AC, handles 50/60 Hz, and carries dual breaking capacities: 15 kA per EN 60898-1 and 25 kA per IEC 60947-2, so it's certified for both residential-distribution and industrial-panel duty under UL 1077 as well.
The dual rating is the headline here. Under EN 60898-1 (the standard for household and similar installations) it's rated 15 kA; under IEC 60947-2 (the industrial standard for low-voltage switchgear) it's rated 25 kA. At 400 V AC, that's enough headroom for a panel fed from a 1000 kVA transformer with typical impedance. For DC circuits it's rated 15 kA at 60 V, stepping up to 72 V max.
Terminals accept combined top and bottom feed, and the supply cord can land on either side.
Halogen-free and silicon-free construction, so it won't outgas corrosive compounds in a sealed panel. Vibration resistance per IEC 60068-2-6 (±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz) means it holds up on a machine skid or near a large motor. Sealable per the standard, and pollution degree 3 (conductive pollution expected).