Rated SCCR of 100 kA at 400 V and 240 V — that's the fault current it can interrupt without welding its own contacts shut. At 500 V it's 42 kA, at 690 V it's 4 kA. Those numbers govern whether this breaker coordinates with the upstream fuse or main, so if you're building a panel for a 400 V line, you've got headroom to the bus. No ground-fault detection on this variant, so keep that in mind if the application needs it separately.
Mounting position any, so you can lay it sideways in a tight gland plate if needed. No screw torque to check, just strip and push. Keep the strip length right and you won't chase a loose connection later. That's the ventilation and arc-chamber space; pack it tighter and the thermal trip shifts.
Current production — not a last-time-buy or NRND. If it's riding in a truck across a desert or sitting in a hot warehouse, that storage range covers it. The fuse backup ratings are given: at 400 V use gL/gG 50 A, at 500 V 40 A, at 690 V 35 A. Those are the max upstream fuse sizes to maintain the SCCR — don't oversize them or you lose the coordination.