It combines a 16 A thermal-magnetic MCB (Curve C, magnetic tripping limit 5...10 x In) with integrated 300 mA Type AC earth-leakage protection in a single 36 mm wide, 1P+N module. The breaking capacity is 4500 A Icn at 230 V AC (EN 61009) and 6 kA Icu at 230 V AC (EN 60947-2). This is the part you spec when you need both overcurrent and earth-leakage protection on a single outgoing circuit — saves a DIN rail slot versus separate devices.
The 16 A rated current (In) with Curve C means the magnetic trip operates between 5 and 10 times In — so 80 to 160 A — which is standard for general-purpose loads like lighting, socket outlets, and small motor circuits where inrush isn't extreme. The 300 mA earth-leakage sensitivity is a common choice for whole-circuit protection where you want to avoid nuisance tripping from leakage in long cable runs or equipment with filters; it's not for personal shock protection (that needs 30 mA or lower).
Snaps onto DIN rail. The 1P+N format (neutral left, phase right) occupies 36 mm (4 x 9 mm pitches). Terminals accept 0.75...16 mm² rigid or 0.33...10 mm² flexible cable upstream and downstream; strip length 13 mm, tighten to 2 N.m.