It is a 4-pole unit configured for line protection with a TM210 thermal-magnetic trip unit, fixed overload setting Ir=16A, and fixed short-circuit protection Ii=20 x In (320A). The N conductor is protected at 100%.
The breaker mounts into a standard 3VA1 panelboard or enclosure footprint. The included nut keeper kit is specified for DC Power OEM installations in China — that's a mechanical fitment aid for the busbar connection, not an electrical rating change. Verify the terminal torque spec against your busbar stack-up before torquing down.