The Siemens 5SN6240-7CP is a 2-pole miniature circuit breaker from the SENTRON 5SN series, rated for 400 V AC at 50 Hz.
The 2-pole configuration switches both phase and neutral on a single-phase circuit, or two phases on a three-phase system where you need independent overcurrent protection on each leg. The DC rating of 72 V maximum means it can also serve in DC control circuits up to that voltage — useful for 48 V or 60 V battery-backed supplies in industrial panels. The 10 000 mechanical operating cycles is typical for a miniature breaker; it is not a contactor, so it is not meant for frequent switching under load, but it will handle routine isolation and occasional fault clearing without issue. In a 2-pole unit that is 7 W total dissipated inside the enclosure.
The 5SN6240-7CP occupies 2 modular width units at 36 mm wide, 76 mm deep, and 90 mm tall, with an installation depth of 70 mm. Accepts solid conductors up to 35 mm², which covers the full range of incoming supply cables for a 2-pole breaker at this voltage class. That -40 °C lower limit matters for outdoor or unheated enclosure installations in cold climates — the breaker's bimetal trip element will still operate correctly at those temperatures. The 75 °C upper limit is the internal enclosure temperature, not the external ambient; if the breaker is in a sealed panel with other heat sources, keep the internal air temperature below that.