That D curve means it's built for loads with high inrush: motor starters, small transformers, discharge lighting. The magnetic trip holds through the startup surge and clears on a hard fault.
Snaps onto standard DIN rail — 18 mm width, one width unit. Mounting position any, so vertical or horizontal busbars work. Depth is 70 mm, same as installation depth; the combined tunnel terminals top and bottom take Cu conductors up to the rated torque of 3.5 Nm.
The D characteristic (10–20× In magnetic trip) is the key selection parameter: if your load is a resistive heater or a general-purpose outlet, you want B or C curve — D is for inductive kicks. For DC circuits, the maximum rated voltage is 60 V — relevant if this lands in a control panel with a 48 VDC bus.