Pack Of 4 40 Watt A19 Ceramic Blue Medium Base Standard Household Incandescent Blue Colored Light Bulb 40 watt incandescent medium based A19 colored bulb works with most 120 volt lighting fixtures Lasts for an average of 1250 hours. This bulb emits a soft blue light that looks great whenever a colored light is needed. Incandescent lighting is commonly used for decorative, office, residential, commercial and special purpose lamps. These bulbs are also great for decorative parties and special purpose lighting applications.