What is the part number for 400A main breaker used in an old NQOB panelboard?

Issue:
400amp Main Circuit Breaker for an NQOB panelboard

Product Line:
Obsolete NOQB Panelboards

Environment:
Products sold in North America

Resolution:
The main breaker was top fed, the part number for the main breaker is LAP36400MT.

Released for:Schneider Electric Ireland