The Schneider Electric MGN19764 is an Acti9 DCP Vigi RCBO — a combined residual current breaker with overcurrent protection (RCBO) in a 2-pole, 16 A rated, 30 mA earth leakage, curve B configuration. It clips onto a DIN rail, takes 4 module pitches (36 mm wide), and is rated to break 10 kA at 220-240 V AC per EN/IEC 61009-2-1. The thermal-magnetic trip unit handles overload and short-circuit; the integrated 30 mA earth-leakage sensor covers ground faults.
Curve B means the magnetic trip fires at 3 to 5 times In — 48 to 80 A for this 16 A unit. That's the right curve for resistive loads and general-purpose circuits with short cable runs where inrush is low. It's not meant for motor or transformer starting where you'd need curve C or D. The 30 mA earth-leakage sensitivity is the standard for socket-outlet circuits and general protection against indirect contact. It's fast enough to protect people but not so sensitive that nuisance tripping from normal cable capacitance becomes a problem. At 4 modules wide (36 mm), it fits a standard DIN-rail enclosure. The toggle gives local ON/OFF/fault-trip indication, and the contact position indicator confirms isolation visually.