THESE ARE "DIALCO" INSTRUMENT PANEL MOUNTED INDICATOR LIGHT ASSEMBLIES. THE LENSES "PUSH IN" , NOT SCREWED IN. USES STANDARD #330 (14VDC) OR #327 (28VDC) LAMPS. MOUNTS INTO A 1/2" HOLE IN PANEL. SOLDER TERMINALS. LENSES CAN BE ENGRAVED FOR NOMENCLATURE.