The Siemens 5SL6616-6CC is a 3+N-pole miniature circuit breaker rated 400 V with a 6 kA breaking capacity, B-curve trip characteristic, and 16 A rated current. This is the standard 4-module (3+N) version for three-phase plus neutral protection in a 400/230 V TN or TT system.
Panel integration note
Snap-on DIN rail mounting per EN 60715. The 3+N-pole unit occupies four 18 mm module widths in the distribution board. Strip length of 8 mm avoids whiskers under the cage.