The Siemens 5SU9336-1CR20 is a 3-pole RCD-operated circuit breaker (RCBO) from the SENTRON 5SU9 family, combining overcurrent and residual-current protection.
The 20 A rating at 30 °C is the headline number, but the thermal derating curve tells the real story: at 40 °C it's 18.6 A, at 45 °C it's 17.6 A, and at 55 °C it drops to 16.6 A. If your enclosure runs warm — say, a packed panel with drives or transformers — size the load to the derated figure, not the 30 °C value.
The 5SU9336-1CR20 occupies 6 width units (108 mm) on a DIN rail, with an installation depth of 70 mm and overall depth of 77 mm.