It's a 3-pole, 10 A, B-curve MCB rated for 400 V AC with a 6 kA breaking capacity per both EN 60898 and IEC 60947-2. It's built for residential buildings and infrastructure, not heavy industrial motor starting.
Mounting position is any, so you can lay it sideways in a tight gland plate without derating. Torque the terminals to 2.5 to 3 N·m — a standard screwdriver setting, no special tool.
Sourcing and fit
If you're filling a BOM line with a 3-pole, 10 A, B-curve MCB, the 5SL6310-6BB is a direct fit — same footprint as other 5SL6 breakers. No neutral switching on this unit (it's a 3-pole only device).