Belmor Smoke Ventvisor for your 1999-2017 Western Star 4900EX FA/SF allows you to enjoy a more comfortable, stylish, and even safer ride when you install a set of Belmor Ventvisor Side Window Deflectors on your truck! Ventvisor Side Window Deflectors combine style, functionality, and protection. Thanks to their unique patented design, fresh air can circulate naturally through your truck's cab while stale air, odors, heat, rain, and snow stay out! They even reduce interior fogging. You'll be more comfortable and stay more alert. Made of smoke-tinted acrylic, Belmor's aerodynamic Ventvisors cover the top of open windows and fully extend down the full length of the side window pillar to minimize difficulties with vision in side mirrors that occur from rain pooling on the side windows. Available in smoke or chrome finishes, Ventvisor Side Window Deflectors add style to your truck as well as enhancing safety and comfort! They install easily using 3M automotive grade tape – no drilling required. Styles fit most popular makes and models including those with high visibility doors and door/cab-mounted mirrors. Engineered, designed, and made in the USA, and backed by a Limited Lifetime Warranty.