SCENT BAR REFILLS: This refill pack has a total of four bars of car air fresheners in the Citrus Sky fragrance. One bar can last for weeks, depending on the intensity setting. The refill bars are also available in other car scents--Speedway, Cinnamon Blast, Evergreen Forest, Amber Vanilla, and Exotic Teak. TURBOCHARGED AIR FRESHENING: The car air fresheners use fragrance-infused resin Scent Bars attached to a diffuser. It then plugs into your car's 12-volt outlet. The car diffuser features a power button with an illuminated LED indicator. It also has an auto shut-off feature that works after one hour of use to help extend the life of your favorite Scent Bar. ACTIVE FRAGRANCE DIFFUSION: While the diffuser is active, the Belle Aroma Scent Bar Refill freshens your car's interior and eliminates bad odors while you drive. To preserve the car scents, the diffuser automatically shuts off after an hour. You can press the reset button to restart. Each Scent Bar provides one week or more of fragrance. ERGONOMIC AND ELEGANT DESIGN: This plug-in car diffuser has an ergonomic, patent-pending design unique in auto fragrance diffusion! The decorative open housing helps optimally diffuse the aroma of the scent bars. One electric air diffuser can last many years. HOW TO REFILL: Drive Time Scent Bar offers a safe, no-mess way to freshen up your car. It doesn't use liquids, gels, or water that can leak and ruin your car's interior! The air fresheners are shaped like soap bars and are easier to use. Pull off the diffuser cap, insert the scent bar into the tray, then replace the cap. Insert the unit into a 12V charger with the on/off LED button facing up. Press the power button to start. Push the button to restart the diffuser when it auto-shuts off.