The H suffix means it's built for higher fault-interruption duty — the specific short-circuit rating is defined by the EasyPact NW H-series curve, but the takeaway is that this chassis is sized for main or feeder breakers in large low-voltage switchgear where you need to pull the cradle for inspection or swap without de-energizing the bus.
Drawout mounting means the chassis slides into a fixed cradle in the switchgear — no bolted connections to the bus. That's the standard arrangement for EasyPact NW frames at this ampacity: you rack the breaker in and out for maintenance without disturbing the main bus connections. Dimensions are 445 mm deep by 400 mm wide by 440 mm tall, so plan for a cubicle depth that clears the cradle travel plus the arc-chamber clearance at the back.
If your switchgear room runs hotter, you'll need to apply the manufacturer's temperature derating curve, but for most industrial low-voltage switchgear applications this is the standard rating. The H breaking capacity code places it in the higher-interrupting-capability tier of the EasyPact NW family, suitable for installations with higher available fault current.