A milky cover serves two functions for a lighting fixture. It offers protection for the bulb from direct contact and it changes the color hue of the bulb.  A milky cover slides over the lamp and the color that you see resembles its name, “milky.” A wire guard can protect your bulbs from damage, theft, and even shattering.  They are commonly used to protect string lighting from falling to the ground but can be used to add aesthetic design in some lighting applications.