The Original Rainbow F/X Light. Use your Rainbow F/X Light in any standard lamp or fixture. Special effects lights are great in Bedrooms, as Porch Lights, at Parties and for Color Meditation. Great Fung Shui. Uniquely colored 40W A-19 bulb emits a beautiful blend of colored light from their deep, rich, fade-free colors. They have been used in theme parks, hotels, commercial and residential applications since 1988. All Rainbow Lights are manufactured using a standard 40-Watt A-19 and are recommended for indoor use only.