Circular metal microphone capsule consisting of a perforated front grill and threaded metal casing with a textured lower section for grip. The top surface features a fine metal mesh with small uniform perforations.
This capsule would have been installed in a field microphone assembly or used as a spare component stored within a military communications valve case (notably the Case Spare Valves No. 4L). The threaded base suggests compatibility with interchangeable radio handsets or signal units.