The MGN61810 is a Schneider Electric Multi9 C60H-DC miniature circuit-breaker, one pole, rated 50 A at 50 °C with a B tripping curve. It's built for DC networks — the thermal-magnetic trip unit is set to magnetic tripping at 5.5 x In +/- 20 % DC, which means it clears short-circuit faults fast on a 110 V, 220 V, or 250 V DC bus. Breaking capacity runs 20 kA Icu at 110 V DC, 10 kA at 220 V DC, and 6 kA at 250 V DC per EN/IEC 60947-2, so it handles the fault energy on a typical DC distribution panel without needing an upstream fuse.
Clip-on DIN rail mount, 18 mm wide (2 x 9 mm pitches), so it takes one slot in a standard enclosure. IP20 on the body, IP40 inside a modular enclosure — fine for dry indoor panels, not for washdown areas. That's enough for a 50 A feed with room for parallel feeds on the load side. Strip length 14 mm, which is standard for this class of breaker.