The model DCB-224 is a high-power spotlight designed and built by Carlisle & Finch. Originally intended for use as an aero beacon, it was also widely used in marine lighthouses.
Depending on the type of bulb installed, the beam could be seen for 18 to 26 nm. The unit consists of a 25 inch aluminum housing with a parabolic reflector. An electric motor and gearbox drives the optical unit's rotation. They can optionally be fitted with a CG-2P automatic bulb changer .
The letters DCB stand for Directional Code Beacon.
References
DCB-224 Wikipedia(Text) CC BY-SA