The Siemens 5SJ6263-7 is a 2-pole SENTRON miniature circuit breaker from the 5SJ6 family, rated 63 A at 400 V AC with a C tripping characteristic and a 6 kA breaking capacity per both EN 60898 and IEC 60947-2.
At 2 width units, it leaves room for adjacent breakers or accessories in a crowded enclosure.
Rated for 20 000 mechanical switching cycles typical, and vibration tested to 50 m/s² at 25–150 Hz and 60 m/s² at 10–150 Hz per IEC 60068-2-6 — solid for use near rotating machinery or on mobile equipment skids.