The Siemens 5SL4416-6CC is a 4-pole miniature circuit breaker (MCB) with a B-curve trip characteristic, rated at 16 A and 400 V AC with a 10 kA breaking capacity. This is the part you need for a 4-pole B16 branch circuit in a 400 V three-phase panel — think lighting, socket outlets, or general-purpose loads where the B-curve handles moderate inrush without nuisance tripping.
If you're sourcing this for a new panel design, the 5SL series is a current catalog line with broad availability across distributors.
RoHS compliant since June 1, 2013, and REACH candidate list information is available from Siemens. Export control is straightforward: AL: N / ECCN: N, so no special licensing for cross-border shipments.