The Siemens 5SU9304-7KK10 is a SENTRON RCBO — an RCD-operated circuit breaker that combines overcurrent protection and residual current detection in a single 18 mm wide module. It's a 1P+N design (switches the line, monitors both line and neutral) with a C-curve tripping characteristic, rated 10 A at 30 °C and breaking 10 kA per EN 60898.
At 40 °C it's 9.4 A; at 45 °C it's 9.1 A; at 50 °C it's 8.7 A; at 55 °C it's 8.1 A. The 5SU9304-7KK10 also carries a 1 kA surge current withstand at 8/20 μS, which covers most lightning-induced transients on a TN system.
Snaps onto standard DIN rail, 18 mm wide (1 modular width unit). Mounting position is any orientation; supply can feed from top or bottom. IP20 rated once installed in a distribution board with conductors connected — so it's strictly for enclosed panels, not standalone outdoor use.