Reflector (R) or Bulged Reflector (BR) 40 bulbs have a reflective coating on the inside of the bulb that directs light forward. Flood types (FL) are flood light bulb types that spread light. Spot types (SP) concentrate the light. Reflector (R) bulbs put approximately double the amount of light (foot-candles) on the front central area as General Service (A) of same wattage. Like all light bulbs, the 40 value represents the diameter of the bulb in 1⁄8 of an inch. Therefore, a R40 is 5 inches in diameter.