The Siemens 5SL6103-7RC is a SENTRON 5SL6 miniature circuit breaker (MCB) — one pole, C-curve, rated 3 A at 230/400 V AC. The 7.5 kA breaking capacity per EN 60898 tells you it can safely interrupt a fault current up to that level without welding its contacts or cascading damage upstream — that's the standard rating for residential and light commercial distribution boards in most European installations. At 3 A, this is sized for a branch circuit feeding a handful of small loads, not a main feeder.
This MCB occupies one width unit (18 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm behind the panel face.
The 5SL6103-7RC carries the standard Siemens compliance package: it's halogen-free and silicon-free, rated for overvoltage category III and pollution degree 2 per IEC 60947-2. The breaking capacity of 7.5 kA is certified per EN 60898. The part is sealable, which means the distribution board cover can be sealed to prevent tampering — common in utility-metered installations. Touch protection is built into the terminals.