The FCA-125-4 is a military/aerospace mid-range relay from the FCA 10–25 Amp Relay Series designed for DC actuating applications requiring reliable single-pole changeover switching. It features a 28 VDC rated coil with a polarized, monostable magnetic system and a 25 A contact rating in a 1 Form C (SPDT) configuration with one changeover contact. The relay employs socket pin termination with gold-plated contacts and is mounted via bottom mount configuration without auxiliary contacts or coil suppression diode. This relay is well-suited for military and aerospace power distribution, load switching, and control applications where high reliability and compact form factor are essential.