The ABB XT5NU340AKFF000XXX is a 400 A three-pole molded case protector (MCP) from the XT5N family, fitted with an EKIP M DIP I electronic trip unit. The FF UL suffix means it carries UL listing, so it's spec'd straight into North American panels without a separate fuse or breaker coordination study.
What the EKIP M DIP I trip unit means in practice
That makes it field-serviceable: you can dial in the protection for a motor load or a feeder without pulling the unit off the DIN rail. The 400 A frame carries the full rated current continuously, and the MCP designation means it's a motor circuit protector — coordinated with a contactor and overload relay upstream for Type 2 coordination in IEC 60947-4-1 schemes.