377-0410-11-203 is a T-3 1/4 miniature bayonet indicator base designed for mounting in an 11/16" clearance hole (.688") with a panel cutout of .660" ± .003". The base features brass solder terminals with hot tinned elongated slots (5/64" × 1/8"), a brass housing with black nickel finish, and includes a brass mounting nut with white nickel finish and a phosphor bronze internal-tooth lockwasher. The assembly uses an 11/16-27 NS threaded mounting bushing and is watertight, meeting MIL-L-3661C military requirements with military cross reference LH77/3. This indicator base is commonly used in ground vehicles, surveillance systems, power distribution centers, aircraft, naval vessels, and underwater applications where reliable visual indication and environmental protection are required.