What this MCB does on the panel
The Siemens 5SY4416-7CV is a 4-pole miniature circuit breaker with a C-curve tripping characteristic, rated 16 A at 35 °C and 440 V AC multi-phase.
Mounting and fit
Occupies 4 modular width units (72 mm wide, 90 mm tall, 76 mm deep, 70 mm installation depth). Combined terminals top and bottom — spring-cage or screw, accepts the usual panel wiring. IP20 with conductors connected; sealable if the panel spec requires it.
Thermal derating — the real-world current
Rated 16 A at 35 °C, but the current drops as ambient rises: 15.12 A at 40 °C, 14.66 A at 45 °C, 14.2 A at 50 °C, 13.68 A at 55 °C. That's the number to use for the BOM, not the 35 °C figure.