A common screw base incandescent lamp. Generally found in older striplights. The "R" indicates a built-in reflector, and the "40" indicates the maximum bulb diameter, in eighths of an inch.
A common screw base incandescent lamp. Generally found in older striplights. The "R" indicates a built-in reflector, and the "40" indicates the maximum bulb diameter, in eighths of an inch.