Protective back cover: The back cover protects the electronics and driver from debris that can fall and damage components while installed in ceilings. Kevlar woofer: The woofer is made from dupont Kevlar fiber with a rubber surround, which helps the speaker produce deep, impactful bass. Silk titanium tweeter: The Silk titanium tweeter delivers sweet and smooth sounding midst and highs, while the variable high-frequency attenuator can accommodate for particularly bright sounding rooms. Magnetic grille: The removable magnetic grille is paintable and features a slim bezel, allowing it to more easily blend into your home's decor.