Kromschröder MNB 25
specifically a relay or control relay part, often utilized alongside Topaz 3-pole configurations—historically specified as a replacement spare part in industrial gas burner management systems and assemblies (such as Nu-way burner control setups).
and a second one of a slightly different style (last 4 pictures)
Component Type: Electrical relay / control component.Brand: Kromschröder (part of Honeywell Thermal Solutions).Application: Used in legacy industrial heating, gas trains, and burner control panels.