The Siemens 5SY6215-8 is a 2-pole miniature circuit breaker from the SENTRON 5SY6 series, rated 1.6 A with a D tripping characteristic. It's rated for AC circuits up to 400 V and DC circuits up to 72 V. Breaking capacity is 6 kA per EN 60898 and 30 kA per IEC 60947-2, with a DC rating of 15 kA per IEC 60947-2 and 5 kA per UL 1077 / CSA C22.2 No. 235. That 30 kA figure gives headroom for industrial panels with high prospective fault current — the 6 kA EN rating covers the residential/commercial side. The part is sealable, halogen-free and silicon-free, and carries IP20 protection with conductors connected.
The D-curve (10-20x In magnetic trip) means it holds through motor starting currents that would trip a C-curve breaker. The operating temperature range is -40 °C to 75 °C, with derating above 55 °C per the humidity table (max 95% RH at 55 °C, 55% at 70 °C, 35% at 75 °C).